In A Large Skillet, Cook Chicken And Onion In Oil Until Onion Is Tender; Remove And Keep Warm. Add Tomatoes, Broth, Basil And Pepper To The Skillet. Bring To A Boil; Stir In Spaghetti. Reduce Heat; Cover And Simmer For 15-20 Minutes. Return Chicken To Pan; Cook Until Juices Run Clear And Spaghetti Is Tender. Sprinkle With Parmesan Cheese.