Preheat the oven to 425 degrees F (220 degrees C). Grease a 9x13-inch casserole dish.
Mix corn, mushrooms, green bell pepper, salsa, tomato, and nacho cheese sauce together in a bowl. Layer mixture over the bottom of the prepared dish. Mix ground beef and taco sauce together in a separate bowl; add to the corn mixture in the dish and stir together. Layer potato puffs on top of casserole. Top with shredded Mexican cheese blend.
Bake in the preheated oven until beef is no longer pink, about 25 minutes.
Set oven rack about 6 inches from the heat source and preheat the oven's broiler. Broil casserole until top is golden brown, about 5 minutes.