Preheat oven to 350 degrees. Grease or spray a 6 cup casserole dish.In a medium skillet over medium-high heat, melt butter. Add onions and diced peppers to the butter and saute for 5-7 minutes or until they start to brown. Once onions are translucent and slightly browned, remove from heat and set aside to cool.
In a medium mixing bowl, combine chopped artichokes, cream cheese, mayo, garlic and seasonings, and mix. Then add the pepper and onion mixture and both kinds of cheese (reserve ¼ cup of shredded Monterrey Jack for the top). Stir mixture until completely combined.
Pour mixture in the prepared casserole dish and spread evenly. Top with remaining cheese and bake at 350 degrees for 20-25 minutes or until bubbly and golden brown. Serve warm with pork rinds, veggies or low carb crackers!