In a large saucepan, heat oil over medium heat until hot. Add onion and garlic; cook and stir 3-5 minutes or until onion is tender. Add broth and tomatoes; bring to a boil. Stir in rotini. Reduce heat; cover and simmer 8-13 minutes or until pasta is just tender. Stir in meatballs and continue to cook until heated through. Garnish each serving with basil and cheese, if desired.