In 12-inch nonstick skillet, heat oil over medium-high heat. Cook chicken and onion in oil 6 to 8 minutes, stirring frequently, until browned and onion is just tender.
Stir in remaining ingredients except parsley. Heat to boiling; reduce heat. Cover and simmer 10 minutes. Uncover and simmer 5 to 8 minutes longer, stirring occasionally, until noodles are tender. Sprinkle with parsley.