In a large mixing bowl, combine ground chicken, canned pumpkin purée, plain breadcrumbs, egg, finely grated garlic, onion powder, salt, and pepper. Use your hands to gently mix until all ingredients are just combined, being careful not to overmix.

With damp hands or a small scoop, portion out the meatball mixture and shape it into 1.5-inch meatballs, aiming for about 16 pieces.

In a nonstick skillet, heat olive oil over medium heat until it shimmers. Carefully add the meatballs in batches, cooking for 2-3 minutes on each side until golden brown and cooked through.

While the meatballs are cooking, in a small saucepan, melt unsalted butter over low heat. Add finely grated garlic and fresh sage, sauté for about 30 seconds until fragrant.

Slowly stir in heavy cream and season with salt, pepper, and optional nutmeg. Allow it to simmer for 3-4 minutes until slightly thickened.

Once the meatballs are golden brown, transfer them into the sage cream sauce and let them simmer for an additional 5-7 minutes.

Serve in shallow bowls, garnished with chopped sage and a sprinkle of black pepper.