Spread one cup of pasta sauce on the bottom of a 9x13 pan.
In a large bowl, mix the cottage cheese, egg, mozzarella cheese, Parmesan cheese, salt, pepper, and nutmeg. Using a piping bag, a spoon, or your fingers, stuff the cheese filling mixture into the manicotti shells.
Place stuffed manicotti on top of the pasta sauce in the pan. Pour the remaining sauce over the top of the pasta.
Thaw.
Preheat the oven to 350°. Remove the foil and plastic wrap from the pan and replace the foil. Bake for 45 minutes.