Spray a 9×13 casserole dish with cooking spray and set aside. Preheat oven to 350 degrees.
Line the bottom of the dish with 6 tortillas (they can overlap). Spread half the refried beans over the top of the tortillas.
Layer 1/3 of the cheese, chicken, corn, chilis and enchilada sauce. Add another layer of tortillas followed by the remaining refried beans.
Top with another 1/4 of the cheese, chicken, corn, chilis and enchilada sauce.
Add the final layer with 6 more tortillas followed by the remaining cheese, chicken, corn chilis, and enchilada sauce.
Bake 35-40 minutes or until cheese is melted and sauce is bubbling.
Let stand 5-10 minutes before serving with optional olives, lettuce, tomatoes and sour cream.