Preheat the oven to 350°F (175°C).

In a large skillet over medium heat, cook the ground beef and chopped onion until the beef is browned and the onion is translucent.

Drain excess fat and stir in the diced tomatoes, beef broth, garlic powder, salt, and pepper.

In a pot, cook the pasta according to package instructions until al dente; drain.

Combine the cooked pasta with the beef mixture and half of the cheddar cheese.

Transfer the mixture to a greased casserole dish and top with the remaining cheddar cheese.

Bake in the preheated oven for 20-25 minutes, or until the cheese is melted and bubbly.