Chicken Fajita Casserole
Fajita chicken, onions, and peppers baked in a creamy cheese sauce? This Chicken Fajita Casserole Recipe may be my favorite casserole yet. It is perfect for busy weeknights with a dollop of sour cream and avocado on top and paired with a fresh green salad.
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I love Mexican food. Since most of my kids love Mexican food too, we add it into the dinner rotation at least a few times a month.
Most of the time, we just have this freezer friendly taco meat (which I do meal prep), but this chicken fajita bake is a welcome step up from a typical Taco Tuesday. Once you try my low carb keto fajita chicken casserole, I guarantee the juicy chicken and melty cheese will make you want to make it again and again. It’s an easy dinner that is quick enough that even if it’s 5 pm, you can make it!
If you are here because you love Mexican food, make sure to try my Keto Taco Salad Casserole Recipe and Keto Chicken Tortilla Soup.
Ingredients
- Chicken Thighs – I prefer using boneless chicken thighs in this recipe but chicken breasts work too. You can also swap in cooked, shredded rotisserie chicken.
- Yellow Onion – Any variety of onions are fine.
- Red Bell Peppers – Sweet bell peppers are the best choice for fajitas.
- Cream Cheese – Adding cream cheese makes a delicious creamy sauce. It’s definitely not traditional but it is SO good. Trust me on this.
- Fajita Seasoning – It is so easy to make your own! Click to learn to make my homemade fajita seasoning: Keto Fajita Seasoning. It uses cumin, paprika, garlic powder, onion powder, chili powder, etc. It is mild enough for the whole family.
- Shredded Cheese – Shredded cheddar cheese, Monterey Jack, or a Mexican blend are all good choices. For a spicier version, try adding Pepper Jack cheese.
See quantities in the recipe card.
How to Make a Chicken Fajita Casserole
Step One: Pop the chicken into the oven to bake in the baking dish or casserole dish you will use for the casserole.
Step Two: While the chicken is baking saute the veggies.
Top Tip💡
Cooking the vegetables in a skillet helps give this casserole a true fajita flavor. Adding raw vegetables and baking does not yield the same result. If you’d like to make this entirely on the oven you can roast the onions and peppers on a baking sheet instead of pan-frying them.
Step Three: Shred the chicken. Then combine the hot shredded chicken with the fajita veggies, cream cheese, and seasonings in a large bowl.
Note: Boneless skinless chicken thighs shred easily but if you choose to use boneless skinless chicken breasts instead it may be easier to just chop them.
Step Four: Put the fajita chicken mixture in the casserole dish, top with cheese, and bake until bubbly and golden. Serve this easy chicken fajita casserole with a salad or your favorite fajita toppings!
Storage
Store leftovers in an airtight container in the fridge for 4-5 days.
Variations
Dairy-Free – Cutting back on dairy and still want fajitas? Try these Baked Chicken Fajitas instead.
Spicy – Sauté some jalapeno peppers along with the peppers and onions. For milder heat, remove the seeds from the jalapenos. Canned green chilies work too.
Chipotle – Add some smokiness with chipotle puree. Simply blend up a can of chipotles in adobo and add a bit to taste to the cooked chicken mix before its added to the casserole pan.
Cast Iron Skillet – Cook the chicken in the pan, remove, cook the peppers and onions, add all of those to a large bowl, add the other ingredients, and mix. Put back into the skillet and bake until hot and bubbly.
Seasoning – To change it up, try my Chicken Taco Seasoning instead of fajita seasoning.
Common Questions
What is Fajita Seasoning?
A blend of spices commonly used for fajitas. I make both my own Homemade Taco Seasoning and Keto Fajita Seasoning. They are quick, easy, and CHEAP!
Can I use chicken breasts?
Yes! Just bake the onions and peppers for 10 minutes before adding strips of raw chicken breasts or they can dry out.
What do I serve with a fajita casserole?
I normally have this on top of cauliflower rice with a green salad on the side. My kids like to add white rice or brown rice, black beans, and tortilla chips. You will definitely want to serve it with traditional toppings like pico de gallo or salsa, sour cream, and guacamole.
Video
Chicken Fajita Casserole
Ingredients
- 10 boneless skinless chicken thighs (about 2 pounds)
- 1 red pepper seeded and sliced into small strips
- 1 large onion peeled and sliced into small strips
- 8 oz cream cheese softened
- 8 oz shredded cheddar
- 1.5 tbsp fajita seasoning
- salt & pepper (optional)
Instructions
- Preheat oven to 350. Put the chicken in the casserole dish you will be using for this dish. Cover with foil and bake until cooked to 160 degrees, about 30-35 min. Cool for a few minutes and then shred or chop into bite-sized pieces. Drain any cooking liquid from the casserole dish.
- Meanwhile, in a frying pan coated with cooking spray, cook the pepper and onion over medium-low heat until they are golden and soft. I let mine caramelize the entire time the chicken was in the oven. I just left the heat between low and medium and popped into the kitchen to give them a stir every 5-10 min. Cool until warm.
- In a large bowl mix the cream cheese, half of the shredded cheddar, and the fajita seasoning. Add the chopped chicken and cooked onion and pepper. Put back into the same casserole dish you cooked the chicken in. Sprinkle on the remaining cheese.
- Bake at 350 for 25-30 min until hot and bubbly.
Notes
Nutrition
Originally Published April 14, 2016. Revised and Republished October 13, 2025.
Oh My Goodness!!! I made this for the first time tonight…it is for a sure a keeper! I used one each – red, yellow and green pepper, as well as an onion, chicken breast fillets and 2 packets of fajita seasoning (since the directions for the packet is 1 pound per packet, so hence 2). The fillets crumbled as I took them out of the casserole dish with the tongs, to mix with cheese and pepper/onion mix. While eating tonight, might guy says “honey, is this one of those low carb things?” I said it sure is! He declared it was better then our usual fajitas I make and he loved it! Thanks for the easy and delicious recipe!
Could this be done in the Instant Pot? I just recently got one and would love to try this in there, just not sure how. 😊
Sure! If you are using raw chicken I would cook that first, remove it, and shred it. I do chicken thighs on manual high pressure for 10 minutes and then natural pressure release. They are so tender. Then saute the veggies. When they are done add the chicken and other ingredients back in and just heat until the cheese melts.
Great, thanks! My instant pot is has a permanent spot on my counter. 😄
Just made this. Don’t know why I waited so long!! My 17 yr old daughter (who thinks your Chicken Bacon Ranch one is the best ever) took one bite and said Oh yeah. She took another bite and said Oh yeah!! For her that is a compliment! Lol! Great recipe!! It’s going into the rotation!!
This was my first time making a casserole and it was delicious. I paired it with cauliflower rice–great low carb meal.
Glad you liked it 🙂
Your recipes look great, but I’m old fashioned and like to print them out. I don’t see a “print this recipe” button. Is there one?
There is one within the recipe box. If you scroll to the bottom of the post, before any reader comments, you should see it.
For the fajita seasoning, do you use store bought? make your own?
I use the fajita seasoning from Penzey’s Spices.
Where can you get that?
From their website. They frequently do free shipping over $20. penzeys.com
Sounds deliciously. Do you have nutrition info?
Yes. I just added a nutrition box to the bottom of the post 🙂
We tried this tonight and I agree with everyone that this is my favorite one of all. Funny because I was wishing that I had added a can of Rotel before baking but when we ate it, it really was perfect. It’s a keeper and would be a great option for a potluck. Thanks!
This looks amazing, I will definitely be trying this soon…
This was the best casserole yet! My entire family loved it! It is going to the church potluck next week!
I made this tonight. It is so good. I made it with chicken breasts because that it what I had. Yummy. The whole family loved it.
This was delicious! Thank you for sharing! 🙂
What is your fajita seasoning? Thanks so mmuch for your great recipes.
I use the fajita seasoning from Penzey’s spices. Their spices are reasonably priced and they always have free shipping over $30. Sometimes over $20.
Hi Taryn,
This sounds pretty incredible! It makes me want to go but the ingredients now and try it (I’m adding it to my grocery list ingredients for this week). Question: do you think it would achieve the same result if thrown into the crockpot, chicken shredded and then baked (broiled for gooey carmeliazation)?
Hi Cynthia, you can definitely cook the chicken in the crock pot. The veggies could probably cook with it. But I would drain the liquid before adding the cheese and spices.
Looks delicious! If I only have boneless breast meat in the house does that just make it a light S?
I’m not sure since it does have a lot of cheese still. I’d say it would still be a regular S.
Makes sense, thanks! Putting on the menu for this weekend!