Preheat oven to 350°F (175°C).
In a skillet, cook the ground beef and onion over medium heat until browned. Drain excess fat.
Season with garlic powder, salt, and pepper. Stir in the tomato soup and mix well.
In a separate bowl, combine the cream of mushroom soup and sour cream.
Layer half of the cooked noodles in a greased 9x13-inch baking dish.
Top with half of the meat mixture, then half of the sour cream mixture, followed by half of the cheese.
Repeat the layers: noodles, meat, sour cream mix, and cheese.
Bake uncovered for 30–35 minutes, until bubbly and cheese is melted.
Let rest for 5 minutes before serving.