Combine the ground chicken, canned pumpkin purée, breadcrumbs, egg, grated garlic, onion powder, salt, and black pepper in a large mixing bowl. Mix until just combined.

Wet your hands and form the mixture into 1.5-inch meatballs, aiming for about 16 meatballs.

Heat olive oil in a skillet over medium heat. Cook the meatballs for 2–3 minutes on each side until golden brown.

Melt unsalted butter in a separate saucepan over medium heat. Add minced garlic and chopped fresh sage, stirring gently for 30 seconds.

Stir in the heavy cream, season with salt and pepper, and simmer gently for 3–4 minutes.

Transfer the cooked meatballs to the simmering sage cream sauce, stirring to coat, and let simmer for an additional 5–7 minutes.

Serve the meatballs and sage cream sauce in shallow bowls, garnished with fresh sage leaves and black pepper.