Cook pasta following package directions; drain. Preheat oven to 350F. Grease 2-quart casserole. In lg bowl, blend ricotta, 1 cup mozzarella, egg, parsley, garlic, pepper & nutmeg; stir in ziti. Spoon into prepared casserole & sprinkle with remaining mozzarella & Parmesan. Bake until top is golden, about 30 min. Makes 8 servings.