1 (32-ounce) package frozen potato rounds
1 (16 ounce) container sour cream
1 cup shredded Cheddar cheese
1 (10.75 ounce) can condensed cream of mushroom soup
1 (6 ounce) can French-fried onions

Preheat oven to 350 degrees F (175 degrees 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 in the 350 degrees F (175 degrees C) oven for 45 to 60 minutes