Bring large pot of water to boiling. Spread 3/4 cup Spicy Tomato Sauce in 12 x 7 x 2-inch baking dish or other 2-quart casserole.
Combine ricotta, basil, oregano, Parmesan, egg, crumbs and nutmeg in large bowl. Let stand 5 minutes.
Heat oven to 375°F.
Once water boils, remove pot from heat. Working with 4 noodles at a time, drop in water; let stand 1 to 2 minutes to soften. Use tongs to transfer 1 noodle to cutting board or work surface. Spread noodle with 3 tablespoons cheese mixture; roll up to enclose filling. Place, seam side down, in sauce-lined baking dish. Repeat with remaining softened noodles. Place 4 more noodles in pot. Fill with cheese mixture. Continue, using up all noodles and cheese mixture. Top with remaining tomato sauce. Sprinkle with mozzarella. Cover with lightly greased foil, greased side down.
To freeze unbaked manicotti, cover with waxed paper, then foil. Refrigerate until cold. Label. Freeze.
Bake, covered, in 375°F oven 30 minutes. Uncover. Bake 15 minutes. Let stand 10 minutes before serving.