01 - Preheat oven to 375°F. Lightly grease a 9x13-inch baking dish.
02 - In a medium skillet over medium heat, sauté the chopped onion for 3 to 4 minutes until softened. Add minced garlic and cook for 1 additional minute.
03 - In a large mixing bowl, combine shredded chicken, sautéed onion and garlic, black beans, corn, and ½ cup enchilada sauce. Mix thoroughly.
04 - Spread ½ cup enchilada sauce evenly on the bottom of the prepared baking dish.
05 - Arrange half of the tortillas over the sauce, slightly overlapping.
06 - Spread half of the chicken mixture over the tortillas. Sprinkle with 1 cup cheddar and ½ cup Monterey Jack cheese.
07 - Repeat layers with remaining tortillas, chicken mixture, and cheeses.
08 - Pour the remaining enchilada sauce evenly over the assembled layers.
09 - Cover with foil and bake for 25 minutes. Remove foil and bake an additional 10 minutes until cheese is bubbly and golden.
10 - Allow to rest for 10 minutes before garnishing with cilantro, green onions, and serving with sour cream and lime wedges.