In a large skillet over medium heat, cook the ground beef or turkey until browned, breaking it up with a spatula as it cooks, about 5-7 minutes.
Add the diced onion to the skillet and cook until softened, about 3-4 minutes.
Stir in the black beans, diced tomatoes with green chilies, taco seasoning, and corn. Mix until everything is well combined and heated through, about 5 minutes.
In a greased 9x13 inch casserole dish, spread half of the crushed tortilla chips in an even layer.
Pour the beef mixture over the chips, spreading it evenly.
Add dollops of sour cream on top, then sprinkle on half of the shredded cheddar cheese.
Add the remaining crushed tortilla chips on top, followed by the rest of the cheese.
If desired, arrange jalapeño slices over the top for extra heat.
Bake the casserole in the preheated oven for 20-25 minutes, or until the cheese is melted and bubbling.
Remove from the oven and let it sit for about 5 minutes before serving.
Garnish with fresh cilantro for a pop of color and flavor before serving.
Notes
Feel free to customize with your favorite toppings.