Cook beef and onion in a Dutch oven over medium heat, stirring until beef crumbles and is no longer pink; drain. Return mixture to pan. Stir in tomatoes, next 7 ingredients, and, if desired, chili powder; bring to a boil. Reduce heat; simmer, stirring occasionally, 30 minutes. Stir in kidney beans and next 3 ingredients; simmer, stirring occasionally, 15 minutes. Stir in pasta. Sprinkle each serving with cheese.