01 - Preheat your oven to 375°F. Lightly grease a 9x13 inch baking dish with cooking spray or a small amount of oil.
02 - In a large mixing bowl, combine the shredded chicken, 1 cup of enchilada sauce, black beans, corn, diced red onion, cumin, chili powder, garlic powder, salt, and pepper. Mix thoroughly until all ingredients are evenly distributed.
03 - Pour 1/2 cup of enchilada sauce onto the bottom of the prepared baking dish and spread it evenly to coat the surface.
04 - Arrange four tortillas over the sauce layer, tearing them as necessary to fit and completely cover the bottom of the dish. Spread half of the chicken mixture evenly over the tortillas, then sprinkle with 2/3 cup of shredded cheese.
05 - Add another layer of four tortillas over the first filling layer. Top with the remaining chicken mixture and another 2/3 cup of shredded cheese, spreading evenly.
06 - Place the remaining tortillas over the top to create the final layer. Pour the remaining 1/2 cup of enchilada sauce evenly over the tortillas. Top with the remaining shredded cheese and black olives if using.
07 - Cover the baking dish tightly with aluminum foil. Bake in the preheated oven for 20 minutes to allow the flavors to meld and the filling to heat through.
08 - Remove the foil and continue baking for an additional 10 minutes, or until the cheese is completely melted, bubbly, and beginning to turn golden brown on top.
09 - Remove from the oven and let the dish rest for 5 minutes before serving. This allows the layers to set and makes cutting easier. Garnish with fresh cilantro, sliced green onions, and avocado. Serve with sour cream and lime wedges on the side.