Preheat your oven to 350°F (175°C) and spray a 9×13 inch baking dish with cooking spray.

In a large skillet over medium-high heat, add the ground beef and cook until browned, about 5-7 minutes.

Stir in the chopped onion and minced garlic, cooking until the onion is translucent and fragrant, roughly an additional 3-4 minutes.

Drain any excess fat from the skillet to keep your casserole nice and light.

Sprinkle in the taco seasoning and mix well to coat the beef and vegetables.

Stir in the black beans, corn, and diced tomatoes with chilies, allowing them to simmer together for 2-3 minutes.

In a separate bowl, combine the cream of mushroom soup and sour cream until smooth.

Start layering the casserole by spreading half of the beef mixture in the prepared baking dish, followed by half of the creamy mixture and a generous portion of shredded cheese.

Top this layer with crushed Doritos and then repeat the layers.

Cover the casserole with foil and bake for 15 minutes, then remove the foil and bake for an additional 10 minutes.

For a finishing touch, set your oven to broil for 2 minutes to crisp the topping.

Remove the casserole from the oven and let it rest for 5-10 minutes before serving.