Preheat the oven to 400°F (200°C).
In a large bowl, combine ground turkey, breadcrumbs, Parmesan cheese, egg, garlic powder, onion powder, and chopped fresh sage. Mix until just combined.
Form the mixture into meatballs, about 1-inch in diameter, and place them on a baking sheet lined with parchment paper.
Bake the meatballs in the preheated oven for 20-25 minutes, until cooked through and browned on the outside.
Meanwhile, prepare the pumpkin sage sauce by combining pumpkin puree, chicken broth, nutmeg, and salt and pepper in a saucepan over medium heat.
Allow the sauce to simmer for about 10 minutes, stirring occasionally, until heated through and slightly thickened.
Once meatballs are baked, gently add them to the pumpkin sauce and stir to coat them evenly.
Serve hot, garnished with additional sage or parsley if desired.