Cook pasta according to package directions; drain and set aside.
Preheat oven to 350°F.
Meanwhile, in a nonstick skillet, cook the beef and onions over medium-high heat until the meat is no longer pink; drain. Return the meat to the pan and stir in the enchilada sauce, seasonings, refried beans, and tomatoes. Fill each pasta shell with some of the mixture. Place the filled shells in a 13x9-inch baking dish coated with non-stick cooking spray.
Cover and bake for 25-30 minutes. Uncover and sprinkle with cheese and bake an additional 5 minutes or until the cheese is melted.
Notes
You can switch out the ground beef for ground or shredded chicken.
A serving is 4-6 shells, depending on how many are in your box or you have filling for.