This well-seasoned king ranch chicken casserole is a big family favorite. You can put the tasty tex-mex casserole together earlier in the day, then cover and refrigerate until you're ready to bake. Make the dish with chicken breasts or chicken thighs, or use a combination of both. This dish is open to all kinds of variations. Feel free to replace one of the cans of condensed soups with 1 cup of sour cream, or, if you aren't a fan of mushrooms, use all cream of chicken soup or half cream of celery. Instead of using all cheddar cheese, use a combination of cheddar and monterey jack cheese, or use part pepper jack cheese for a spicier topping. If you don't have a can of tomatoes with green chilies (ro-tel or similar), substitute with plain diced tomatoes and a small can of chopped green chili peppers. The casserole may be made with flour tortillas as well. Serve with a tossed salad for an uncomplicated and fabulous family meal.