Spray a 9x13 baking pan with cooking spray. Place chips in the bottom of the baking pan.
In a medium bowl, mix together the diced/shredded cooked chicken, cream of chicken soup, green chilis, sour cream, onion, milk, garlic salt, salt and pepper. Pour on top of the tortilla chips in the baking pan. Sprinkle cheddar cheese and Monterrey Jack cheese on top.
Bake at 350 degrees for 30 minutes.
Serve with lettuce, avocado, tomato or salsa.
Recipe by Saving Cent by Cent at https://savingcentbycent.com/2018/10/24/chicken-enchilada-tortilla-chip-casserole/