Preheat your oven to 350°F.
In a large skillet over medium heat, cook the ground beef and diced onion until the beef is browned and the onion is translucent, about 5-7 minutes. Drain any excess fat.
Stir in the black beans, corn, diced tomatoes, and taco seasoning. Cook for an additional 3-5 minutes until heated through.
In a large mixing bowl, combine the beef mixture with 1 cup of cheddar cheese, sour cream, and salsa. Mix until well combined.
In a greased 9x13-inch baking dish, layer half of the crushed Doritos on the bottom.
Spread the beef mixture evenly over the Doritos.
Top with the remaining crushed Doritos and the rest of the cheddar cheese.
Bake in the preheated oven for 25-30 minutes, or until the cheese is melted and bubbly.
If desired, garnish with chopped cilantro before serving.