Preheat the oven to 350°F. Grease a 9x13 casserole dish.
Dice the potatoes into ½-1 inch pieces.
In a medium skillet, cook the ground beef with garlic powder, pepper, and salt over medium-low heat. Break the meat apart as it cooks until no longer pink. Drain any excess grease.
In a large bowl, mix the cooked beef, diced potatoes, thawed mixed veggies, and both soups. Pour the mixture into the casserole dish.
Sprinkle shredded cheddar cheese over the top. Cover with aluminum foil and bake for 40 minutes.
Remove the foil and bake for an additional 15-20 minutes, or until the potatoes are tender.