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 enchilada sauce evenly across the bottom of the prepared baking dish. Arrange four tortillas over the sauce, tearing as necessary to cover the base completely.
04 - Distribute half of the chicken mixture evenly over the tortilla layer. Sprinkle with 2/3 cup of shredded Mexican cheese blend.
05 - Place another layer of tortillas over the cheese. Top with remaining chicken mixture and another 2/3 cup cheese.
06 - Arrange final tortilla layer over the filling. Pour remaining 1/2 cup enchilada sauce evenly over tortillas. Top with remaining cheese and black olives if desired.
07 - Cover baking dish tightly with aluminum foil. Bake for 20 minutes to heat through and meld flavors.
08 - Remove foil and return to oven for 10 additional minutes until cheese is bubbly and lightly golden. Remove from oven and let rest for 5 minutes.
09 - Top bake with fresh cilantro, green onions, and sliced avocado. Serve warm with sour cream and lime wedges on the side.