Cook pasta according to package directions; rinse with cold water. Drain and set aside.
Process tomato sauce and diced tomatoes and green chilies in a blender 20 seconds or until smooth. Set aside.
Remove casings from sausage, and discard. Cook sausage in a large skillet over medium-high heat, stirring until meat crumbles and is no longer pink. Drain sausage, if desired, and return to skillet. Stir in cream cheese, ricotta cheese, and 2 cups mozzarella cheese. Spoon into manicotti shells; arrange stuffed manicotti in a lightly greased 13x9 inch-baking dish.
Pour tomato mixture over shells; sprinkle with remaining 2 cups mozzarella cheese.
Bake at 350 degrees for 20 minutes or until cheese is melted and bubbly. Let casserole stand 10 minutes before serving, Sprinkle top with chopped fresh parsley, if desired.
Note: Casserole may be assembled and frozen up to 1 month. Thaw in refrigerator overnight; bake, covered, at 350 degrees for 30 minutes or until cheese is melted and bubbly.
Ground beef and tomato manicotti: Substitute 1 pound lean ground beef for sausage. Stir in 1/2 teaspoon dried Italian seasoning, 1-teaspoon salt, 1-teaspoon pepper, and 1-teaspoon fennel seed. Proceed as directed.