01 - Preheat your oven to 375°F (190°C). Lightly grease a 9x13 inch (23x33 cm) baking dish.
02 - In a large bowl, combine shredded chicken, 1 cup enchilada sauce, black beans, corn, red onion, cumin, chili powder, garlic powder, salt, and pepper. Mix until well combined.
03 - Spread 1/2 cup of enchilada sauce on the bottom of the prepared baking dish. Layer four tortillas over the sauce, tearing as needed to fit and cover the bottom.
04 - Spread half the chicken mixture evenly over the tortillas. Sprinkle with 2/3 cup shredded cheese.
05 - Add another layer of tortillas, then top with the remaining chicken mixture and another 2/3 cup of cheese.
06 - Place the final layer of tortillas over the top. Pour the remaining 1/2 cup enchilada sauce evenly over the surface. Top with the remaining cheese and sliced black olives if using.
07 - Cover with foil and bake for 20 minutes.
08 - Remove the foil and bake uncovered for an additional 10 minutes, or until the cheese is bubbly and golden.
09 - Let rest for 5 minutes before garnishing with cilantro, green onions, avocado, and serving with sour cream and lime wedges.