Preheat oven to 325 degree F. Cook noodles according to package directions. Drain; rinse. Combine sausage, chicken, Cajun seasoning, and sage. In a large skillet cook meat mixture 8 minutes or until chicken is no longer pink. Remove from skillet using a slotted spoon, reserving drippings in skillet. Set meat mixture aside; keep warm. In same skillet cook onion, celery, sweet pepper, and garlic in drippings until vegetables are tender. Stir in meat mixture, one container of the Alfredo sauce, and Parmesan cheese.
Lightly coat a 13x9x2-inch baking dish or 3-quart rectangular casserole with nonstick spray. Arrange 4 noodles in bottom of dish. Spread with 2 cups of the meat-vegetable mixture. Sprinkle with 1/2 cup of the mozzarella. Repeat layers, ending with noodles. Carefully spread remaining Alfredo sauce over the top (if sauce is too thick, heat slightly). Cover; bake 1 hour or until heated through. Let stand 15 to 20 minutes before carefully cutting. Makes 12 servings.