Preheat oven to 400.
Brown the ground beef with the minced onion and garlic powder. Drain.
Add the browned ground beef to the bottom of a 9x13-inch baking dish. Add several lines of BBQ sauce or ketchup over the ground beef. Add the mixed veggies over the top and then spread the tater tots on top. Lastly, add the shredded cheddar cheese over the tater tots.
Bake in the preheated oven for 25 minutes, or until tater tots are warmed and cheese has melted.
Serve Tater Tot Shepherd's Pie.
To Freeze: Prepare the casserole as directed. After you sprinkle the cheese on top, you can cover the disposable baking tray or casserole dish with foil and freeze. To reheat: let thaw and bake as directed. If cooking from partially thawed or frozen, bake twice as long...half of the time covered with the foil and the other of half of the time uncovered.