1 (32 oz.) package frozen potato rounds
1 (16 oz.) container sour cream
1 cup shredded Cheddar cheese
1 (10-3/4 oz.) can condensed cream of mushroom soup
1 (6 oz.) can French-fried onions
Preheat oven to 350°F. (175°C.). Grease a 9x13 inch-baking dish. Arrange tater tots in the prepared baking dish. In a mixing bowl, combine sour cream, cheese, and mushroom soup.
Pour this mixture over the tater tots. Sprinkle onions over the top of the casserole.
Bake for 45 to 60 minutes.