Preheat oven to 350°F and grease a 13x9 casserole dish.
In a skillet, cook ground beef (or turkey), onion, bell pepper, and garlic; drain fat.
Mix in salsas, taco seasoning, and ⅓ cup chicken stock, cooking until liquid thickens, about 4-5 minutes. Remove from heat.
In a bowl, combine meat mixture, sour cream, black beans, cream of mushroom, and half the cheese.
Layer 2 cups of Doritos, half the meat mixture in the dish, and repeat. Top with another 2 cups of Doritos and remaining cheese.
Cover with foil and bake for 30 minutes. Remove foil, add extra cheese, and bake until cheese melts.
Cool for 10 minutes, garnish, and serve.