01 -
Preheat oven to 350°F. Lightly spray a 9x13-inch casserole dish with nonstick spray.
02 -
Gently crush Doritos: finely crush 2 cups almost to a breadcrumb texture; keep 1 cup as larger chunks for topping.
03 -
In a large skillet, cook ground beef and diced onion over medium heat until browned. Drain excess grease. Add minced garlic and cook for 1 minute until fragrant.
04 -
Stir in frozen corn, taco seasoning, undrained diced tomatoes with green chilies, and 2 cups of finely crushed Doritos. Remove from heat and fold in sour cream and 2 cups of shredded Mexican cheese.
05 -
Transfer mixture to prepared casserole dish. Bake uncovered for 5 minutes until warmed through.
06 -
Sprinkle remaining 1 cup shredded cheese evenly over casserole, then top with 1 cup loosely crushed Doritos. Bake for an additional 5 minutes until cheese is melted.
07 -
Remove from oven and garnish with sliced green onions, diced tomatoes, shredded lettuce, avocado, and additional sour cream as desired. Serve immediately.