Preheat the oven to 375°F.
In a large skillet over medium-high heat, brown the ground beef and onion until no pink remains. Drain any fat.
In a medium bowl, mix the thawed vegetables, soup, milk, seasonings, beef mixture, and ½ cup shredded cheese.
Spread the beef mixture into a 3qt or 9x13-inch baking dish. Sprinkle the remaining cheese on top.
Top with tater tots and bake for 40 to 50 minutes or until the sauce is bubbly and the tots are golden brown.
