Preheat oven to 350°. In a large skillet over medium heat, heat oil. Add onion and pepper and cook until soft, 5 minutes. Add garlic and cook until fragrant, 1 minute more. Add beans, corn, chicken, and green chilis and cook until warmed through, 5 minutes. Reserve ½ cup enchilada sauce then pour remaining sauce into skillet, stirring to combine.
Mix in half cheese
Cut up 4 tortillas into bit size pieces and add to cheese mixture
Grease pan and place 4 tortillas to cover base of pan.
Place chicken mixture into pan cover with remaining cheese to cover chicken.
Cook for 39-40 minutes until cheese is melted