Preheat your oven to 350°F (175°C).
In a skillet, cook the ground beef or turkey over medium heat until browned.
Drain excess fat from the meat.
Add taco seasoning, black beans, and diced tomatoes to the skillet; stir well.
In a greased 9x13 inch baking dish, layer half of the Doritos at the bottom.
Spread half of the meat mixture over the Doritos.
Layer half of the sour cream over the meat.
Sprinkle half of the cheddar and Monterey Jack cheese on top.
Repeat the layers with the remaining ingredients.
Bake for 25-30 minutes or until cheese is bubbly and golden.