In a large mixing bowl, combine the shredded chicken, black beans, corn, diced tomatoes with green chilies, and taco seasoning. Mix well until all ingredients are coated with the seasoning.
In a greased 9x13 inch baking dish, spread half of the crushed tortilla chips evenly at the bottom.
Spoon half of the chicken mixture over the tortilla chips, followed by a layer of half the cheddar cheese.
Repeat the layers: add the remaining tortilla chips, then the rest of the chicken mixture, and top with the rest of the cheddar cheese.
In a separate bowl, mix the sour cream with a splash of lime juice (optional for added freshness). Spread this mixture over the top layer of cheese.
Cover the baking dish with aluminum foil and bake for 25 minutes.
After 25 minutes, remove the foil and bake for an additional 10–15 minutes or until the cheese is bubbly and golden.
Once it's done, remove from the oven and let it cool for a few minutes. Garnish with chopped cilantro, diced avocado, and slices of jalapeño if desired.
Slice and serve warm, either directly from the dish or plated alongside a fresh green salad.
Notes
For added freshness, mix sour cream with a splash of lime juice.