Add chicken stock to a deep pot and bring up to a simmer.
While waiting for the stock to heat, combine the ground meat with egg, bread crumbs, cheese, nutmeg, and salt and pepper in a bowl. Roll into small walnut-size balls. Once stock is simmering, add meatballs. Let the stock come back up to a simmer then add the tortellini and cook according to package directions.
While the dumplings and tortellini are cooking, place the parsley leaves, lemon zest and garlic in a pile on your cutting board. Run you knife through it until it is finely chopped and mixed together.