Cook chicken breasts and shred or cube then set aside. Preheat oven to 400 degrees.
Blend can of stewed tomatoes and enchilada sauce in a blender until smooth. In a large pot, heat olive oil and saute red onion and bell pepper until tender. Add the enchilada sauce, corn and spinach then simmer for 3-4 minutes. Drain and rinse beans. Then add seasonings, chicken, and beans. Simmer for about 5 minutes. Finally, add about 2 hand fulls of cheese.
Have a casserole dish ready and begin assembling. First lay down a layer of tortillas, then a layer of the mixture. Continue this ending with a layer of tortillas on top. Put a generous layer of cheese on top.
Place casserole in the oven for 20 minutes or until cheese is golen brown.