1.In A Saucepan, Cook Macaroni In Boiling Water For 5 Minutes. Stir In Onion. Cook 1-2 Minutes Longer Or Until Macaroni Is Tender; Drain. 2.In Another Saucepan, Combine The Chili And Soup; Heat Through. Stir In Macaroni And 3/4 Cup Of Cheese. Transfer To A Greased 11-In. X 7-In. X 2-In. Baking Dish. Cover And Bake At 350 Degrees F For 20 Minutes. Uncover; Sprinkle With Remaining Cheese. Bake 5-10 Minutes Longer Or Until Cheese Is Melted.