Use rotisserie chicken or leftover cooked chicken to save time. For a creamier texture, substitute half the sour cream with cream cheese. Warm the tortillas slightly before cutting to prevent cracking. Don't skip the resting time after baking; it helps the casserole set for easier slicing. If you prefer a spicier dish, add extra diced green chilies or a sprinkle of cayenne pepper. Leftover casserole can be reheated in the oven or microwave, but cover to retain moisture. For a crispier top, broil the casserole for the last 2-3 minutes, watching closely to avoid burning.