Preheat your oven to 375°F.
This initial step helps get your oven ready for baking.
In a large bowl, mix the enchilada sauce, cream of chicken soup, green chilies, and sour cream.
This forms a delicious and creamy base!
Spread a thin layer of the sauce mixture onto the bottom of a 9×13-inch baking dish.
Layer tortillas, shredded chicken, diced onion, and jalapeño in the dish.
Repeat with a layer of sauce and cheese.
Repeat layers until all ingredients are used, finishing with cheese on top.
Bake uncovered for about 25-30 minutes or until bubbly.
Serve hot!