Preheat oven to 375°F (190°C) and lightly grease a 9x13 inch baking dish.
In a large skillet over medium-high heat, brown the ground beef with diced onions until meat is fully cooked.
Drain any excess grease from the skillet.
Stir in minced garlic, Worcestershire sauce, salt, and pepper and cook for 1 minute.
Spread the beef mixture into an even layer in the bottom of the prepared baking dish.
Spread the condensed cream of mushroom soup evenly over the beef layer.
Layer the drained green beans over the soup layer.
Sprinkle 1 cup of the shredded cheddar cheese over the green beans.
Arrange the frozen tater tots in a single, tight layer across the entire top of the casserole.
Bake uncovered for 35 to 40 minutes until the tater tots are golden brown and crispy.
Sprinkle the remaining 1 cup of cheese over the tots and bake for an additional 5 minutes until the cheese is melted and bubbly.