Preheat your oven to 350°F (175°C). Grease a 9×13-inch baking dish with cooking spray or butter.
Sauté the Vegetables:
In a large skillet, heat the olive oil over medium heat. Add the diced onion and bell pepper. Sauté for about 4-5 minutes until softened.
Make the Sauce:
To the skillet, add the cream of chicken soup, cream of mushroom soup, diced tomatoes with green chilies, chicken broth, chili powder, cumin, garlic powder, salt, and pepper. Stir everything together and bring to a simmer. Let it cook for about 5-7 minutes until the mixture is heated through and well combined.
Combine the Chicken:
Add the shredded chicken to the skillet, stirring to coat the chicken in the creamy sauce. Let it cook for another 2 minutes to warm the chicken through.
Assemble the Casserole:
In the prepared baking dish, layer the bottom with about 1/3 of the tortilla strips.
Spread 1/3 of the chicken mixture over the tortillas.
Sprinkle 1/3 of the shredded cheese over the chicken mixture.
Repeat the layering process two more times: tortillas, chicken mixture, cheese. The top layer should be cheese.
Bake the Casserole:
Cover the casserole with aluminum foil and bake for 25 minutes. Then, remove the foil and bake for an additional 10-15 minutes, or until the cheese is bubbly and golden brown.
Serve:
Let the casserole sit for 5-10 minutes before serving. Garnish with freshly chopped cilantro, if desired, and serve with a side of rice, beans, or a simple salad.