01 - Preheat oven to 375°F and lightly grease a 9x13 inch 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 thoroughly incorporated.
03 - Spread 1/2 cup 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 dish bottom completely.
05 - Spread half the chicken mixture evenly over the tortillas. Sprinkle with 2/3 cup shredded cheese.
06 - Add another layer of tortillas, then distribute remaining chicken mixture evenly and top with another 2/3 cup cheese.
07 - Place final tortilla layer over the top. Pour remaining 1/2 cup enchilada sauce evenly across surface. Top with remaining cheese and black olives if using.
08 - Cover with foil and bake for 20 minutes. Remove foil and bake uncovered for an additional 10 minutes, until cheese is bubbly and golden brown.
09 - Let bake rest for 5 minutes before garnishing with cilantro, green onions, avocado, and serving with sour cream and lime wedges.