In a large bowl, combine sausage and cottage cheese. Stuff into manicotti shells. To easily fill the shells, place the mixture into a 1 gallon ziplock storage bag and cut off a corner. Then squeeze the mixtures into the shells.
Place in a greased 13-in. x 9-in. baking dish. Top with baking sauce.
Cover and bake at 350° for 55-60 minutes or until a meat thermometer inserted into the center of a shell reads 160°.
Uncover; sprinkle with mozzarella cheese. Bake 8-10 minutes longer or until cheese is melted. Let stand for 5 minutes before serving.