Preheat oven to 350°. Cook noodles according to package directions for al dente; drain., In a 6-qt. stockpot, cook beef and onions over medium-high heat until beef is no longer pink, 10-12 minutes, breaking beef into crumbles; drain. Stir in bacon, tomato sauce, tomatoes, sugar and salt; heat through., Spread 1 cup sauce into each of 2 greased 13x9-in. baking dishes. Layer each with 4 noodles, overlapping as needed, 1-2/3 cups sauce and 1-1/3 cups cheese. Repeat layers twice., Bake, covered, 40 minutes. Uncover; bake until bubbly, 5-10 minutes longer. Let stand 15 minutes before serving.