Cook pasta shells according to package directions. Drain shells; rinse with cold water and drain well. Set shells aside. Preheat oven to 350 degree F.
Meanwhile, for filling, in a large bowl stir together the eggs, ricotta cheese, 1 cup of the mozzarella, 3/4 cup of the Parmesan cheese, the walnuts, parsley, salt, pepper, and nutmeg.
Spread 1 cup of Classico(R) Four Cheese pasta sauce in the bottom of a 3-quart baking dish. Spoon a heaping tablespoon of filling into each cooked shell. Arrange filled shells in the baking dish. Pour remaining Classico(R) Four Cheese pasta sauce over shells. Sprinkle with the remaining mozzarella and Parmesan cheeses. Bake, covered, about 45 minutes or until heated through.