In frying pan over high heat, add vegetable oil, onions, red pepper, green pepper and stir it well. Cook for 2 minutes until vegetables are soft and tender. Remove vegetables from the heat and transfer to a bowl.
Make Vegetable Filling
Then mix together chicken broth, cream of mushroom soup, cream of chicken soup, sour cream, tomatoes with green chilies, dried oregano, cumin powder, chile powder, chipotle powder, salt in the cooked vegetables bowl.
Assemble Chicken Casserole
To assemble chicken casserole, Cut corn tortillas into quarters. Add a layer of vegetable filling, layer of shredded chicken and add layer of tortilla pieces. Then add layer of vegetable filling and layer of cheese over tortilla pieces. Then again add layer of tortilla pieces, shredded chicken, vegetable filling, cheese and finally add layer of tortilla pieces, vegetable filling and top with cheese. Place chicken casserole in the oven and bake for 40 minutes. Remove chicken casserole from the oven and serve with corn and sliced tomatoes. Your Chicken Casserole is ready to serve. Enjoy!