Cook and stir meat and onions in large skillet or Dutch oven until meat is brown. Drain off fat. Stir in tomatoes (with liquid) and remaining ingredients except Cheddar cheese; break up tomatoes. TO COOK IN SKILLET: Heat mixture to boiling. Reduce heat; cover and simmer, stirring occasionally, until spaghetti is tender, about 30 minutes. (A small amount of water can be added if necessary.) Sprinkle with cheese. Cover and heat until cheese is melted. TO COOK IN OVEN: Pour mixture into ungreased 2or 2 1/2-quart casserole. Cover and bake in 375' oven, stirring occasionally, until spaghetti is tender, about 45 minutes. Uncover; sprinkle with shredded Cheddar cheese and bake about 5 minutes.