01 - Preheat oven to 375°F. Lightly grease a 9x13 inch baking dish with cooking spray or oil.
02 - In a large bowl, combine shredded chicken, 1 cup 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 - Spread 1/2 cup of enchilada sauce evenly across the bottom of the prepared baking dish.
04 - Arrange four tortillas over the sauce, tearing as necessary to fit and cover the entire bottom surface.
05 - Distribute half the chicken mixture evenly over the tortillas. Sprinkle with 2/3 cup shredded cheese.
06 - Place another layer of tortillas over the filling. Top with remaining chicken mixture and another 2/3 cup cheese.
07 - Arrange final tortilla layer on top. Pour remaining 1/2 cup enchilada sauce evenly over surface. Top with remaining cheese and black olives if using.
08 - Cover dish tightly with aluminum foil. Bake for 20 minutes to heat through.
09 - Remove foil and continue baking for 10 minutes until cheese is bubbly and golden brown. Let rest for 5 minutes before serving.
10 - Top with fresh cilantro, green onions, and sliced avocado. Serve with sour cream and lime wedges on the side.