Step 1: Preheat your oven to 375°F (190°C) and lightly grease a 9x13-inch baking dish. If your chicken isn't already cooked, poach it in simmering water for about 15 minutes until the internal temperature reaches 165°F, then shred using two forks. Pro tip: Slightly undercook the chicken as it will continue cooking in the oven, ensuring it stays juicy in the final dish.
Step 2: Heat olive oil in a large skillet over medium heat. Add onions and sauté for 3-4 minutes until translucent. Add garlic and cook for an additional 30 seconds until fragrant. The aroma filling your kitchen at this point will already have family members wandering in to ask about dinner!
Step 3: Add the shredded chicken to the skillet with onions and garlic. Sprinkle the taco seasoning over the chicken and stir to coat evenly. For the richest flavor development, allow the seasoning to toast slightly for about 1 minute before proceeding.
Step 4 : Add diced tomatoes with green chilies, black beans, corn, and diced bell pepper to the chicken mixture. Stir everything together until well combined and simmer for 5 minutes to meld the flavors. This vegetable mixture adds vibrant color, essential nutrients, and textural contrast to your chicken taco casserole.
Step 5: Begin layering your casserole with half of the tortilla triangles arranged on the bottom of the prepared baking dish. Spread half of the chicken mixture over the tortillas, then sprinkle with 3/4 cup of the cheese. Repeat with remaining tortillas, chicken mixture, and top with the remaining cheese. This layering technique ensures that every bite contains the perfect balance of ingredients.
Step 6: Cover the baking dish with aluminum foil and bake for 20 minutes. Then remove the foil and bake for an additional 10-15 minutes until the cheese is bubbly and golden. The contrast between the melty interior and slightly crispy top will make this chicken taco casserole irresistible!
Step 7: Allow the casserole to rest for 5-10 minutes before serving. This resting period is crucial as it allows the layers to set and makes serving much easier. Top with dollops of sour cream and sprinkle with fresh cilantro just before serving to enhance both visual appeal and flavor complexity.