Preheat oven to 350 degrees. In bowl, combine Ready Pac Foods® Spinach, ricotta, 2/3 cup mozzarella cheese, Ready Pac Foods® Diced Onions, Parmesan cheese, eggs and nutmeg; blend well. Stuff the cooked shelled with filling. Pour half the pasta sauce in a greased 13x9x2-inch-baking dish. Arrange the stuffed shells in baking dish; top with remaining sauce and mozzarella cheese. Bake, uncovered, for 30 minutes.