This recipe has been in my family since I was a kid, and I'm a senior citizen now. For years I made it with cheddar cheese, now I make it with cheddar, Monterey Jack, and Colby, and boy, what a difference!
Boil the chicken with 1/2 cup onion and the salt and pepper until meat falls off the bones (about 1 hour), save the chicken stock for use later. Let the chicken cool, then slice the into 1/4 to 1/2 inch cubes.
Mix 1/2 cup of the chicken stock with all the other remaining ingredients except the cheese and tortillas.
Mix the three cheeses together.
Dip tortillas into remaining reserved chicken stock and put a double layer of tortillas in two 8 inch x 8 inch pans (I use two 2 quart Pyrex glass ones), a layer of the soup, vegetables and chicken mixture, a layer of 1/3 of the cheese, then repeat these layers two more times.
Cover with tinfoil and bake at 300 degrees for 1 hour.
Let the dish set for 10 minutes before serving. This recipe results in a mildly hot dish. If you would like it hotter, increase the three peppers, or just serve with a jar of ground cayenne pepper, so each person can adjust the heat as they like.