Preheat oven to 350°F.

In a large skillet, cook ground beef and chopped onion over medium heat until beef is browned; drain excess fat.

Stir in cream of mushroom soup, sour cream, salt, and pepper. Mix well.

Spread beef mixture evenly in a greased 9×13-inch baking dish.

Sprinkle turkey bacon and 1 cup of shredded cheese over the beef.

Arrange frozen tater tots in a single layer on top.

Bake uncovered for 40–45 minutes until tater tots are golden brown.

Sprinkle remaining cheese over the casserole and bake 5 more minutes until melted.