1Cook beef and about 1 1/2 cups of the onion in 4-quart Dutch oven over medium heat 8 to 10 minutes, stirring occasionally, until beef is brown and onion is tender; drain.
2Stir in tomatoes, beans, tomato sauce and chili powder, breaking up tomatoes. Cook uncovered over medium heat about 10 minutes, stirring occasionally, until desired consistency. Meanwhile, cook and drain spaghetti as directed on package.
3Cover and refrigerate half of chili for another meal. Spoon remaining chili over hot spaghetti; sprinkle with cheese and remaining onion.