Preheat your oven to 375°F. In a large, deep skillet or pot, cook and crumble the ground beef over medium-high heat for 2 minutes. Add the onions and continue cooking for another 5 minutes, or until the beef is browned and the onions are tender. Drain any excess grease.

Stir in the Manwich sauce, chicken broth, and undrained diced tomatoes. Bring the mixture to a gentle boil, then add the pasta and stir to combine. Cover and let it simmer until the pasta is al dente, stirring occasionally to prevent sticking. You may need to cook it a bit longer than the package instructions since it's simmering gently. Test a noodle for doneness before proceeding.

Reduce the heat to low, add the cubed Velveeta and cover the pot to allow it to melt. Stir gently to blend everything together.

Transfer the mixture to a lightly greased 9 x 13 inch casserole dish. Sprinkle shredded cheddar on top. Cover and bake for 15 minutes, then remove the cover and serve with cornbread!