Preheat oven to 350°F (175°C).

Brown ground beef in a skillet and drain off any excess grease.

In a bowl, mix together the enchilada sauce, green chilies, cream of mushroom soup, and cream of chicken soup.

In a casserole dish, create a layer of tortilla chips.

Spread half of the browned ground beef over the tortilla chips.

Sprinkle about 1/2 cup of chopped onion over the beef.

Sprinkle 1 cup of grated Cheddar cheese over the onions.

Pour half of the soup mixture over the cheese.

Repeat the layers: tortilla chips, remaining ground beef, remaining onions, remaining cheese, and remaining soup mixture.

Bake in the preheated oven for approximately 45 minutes, or until the casserole is bubbly and heated through.