Preheat the oven to 350°F (175°C).
In a large mixing bowl, combine the shredded chicken, black beans, corn, diced tomatoes, salsa, chili powder, cumin, and garlic powder. Mix well until all ingredients are evenly combined.
In a greased 9x13-inch baking dish, layer half of the tortilla strips on the bottom.
Spread half of the chicken mixture over the tortilla strips, then sprinkle with 1 cup of shredded cheddar cheese.
Repeat the layers with the remaining tortilla strips, chicken mixture, and top with the remaining cheese.
Cover the baking dish with aluminum foil and bake for 25 minutes.
Remove the foil and bake for an additional 10-15 minutes, or until the cheese is bubbly and golden brown.
Remove from the oven and let it cool for 5 minutes. Garnish with chopped cilantro if desired. Serve with sour cream on the side.