Preheat the oven to 375°F (190°C) and lightly grease a 9x13-inch casserole dish.

Heat the olive oil in a large skillet over medium heat. Add the diced onion and cook for 3 to 4 minutes, until softened. Stir in the garlic and cook for 30 seconds more.

Add the shredded chicken and taco seasoning to the skillet, stirring to coat the chicken evenly.

In a large bowl, combine the seasoned chicken mixture, black beans, corn, diced tomatoes with green chilies, cooked rice, salsa, sour cream, 1 1/2 cups of the shredded cheese, salt, and black pepper.

Fold in the tortilla strips until everything is evenly mixed.

Spread the mixture evenly into the prepared casserole dish. Sprinkle the remaining 1/2 cup cheese over the top.

Bake for 25 to 30 minutes, until hot and bubbly and the cheese is melted and lightly golden.

Let the casserole rest for 5 minutes before serving. Garnish with cilantro and green onions if desired.