Preheat oven to 350°F and grease a 9x13-inch baking dish.
Sauté onion and bell pepper in butter over medium heat until softened, about 5 minutes.
In a large bowl, mix together both soups, Rotel tomatoes, chicken broth, chili powder, cumin, and garlic powder.
Stir in the sautéed vegetables and shredded chicken until well combined.
Layer half the tortilla strips in the bottom of the baking dish.
Spread half the chicken mixture over tortillas, then sprinkle with half the cheese.
Repeat layers with remaining tortillas, chicken mixture, and cheese.
Bake uncovered for 40-45 minutes until bubbly and cheese is golden brown on top.