In a large bowl, combine ground chicken, ricotta, Parmesan, breadcrumbs, egg, minced garlic, chopped parsley, salt, black pepper, and dried oregano. Use your hands to mix gently until just combined; be careful not to overmix.

Using your hands, form the mixture into meatballs, aiming for a size of about 1.5 inches (4 cm) in diameter.

Heat a drizzle of olive oil in a large skillet over medium heat. Carefully add the meatballs to the pan without overcrowding and sear them on all sides until golden brown, about 5-6 minutes total.

Once browned, remove the meatballs from the pan and set aside.

In the same skillet, add more olive oil if necessary and sauté minced garlic until fragrant, about 30 seconds.

Add the chopped spinach to the pan and cook until wilted, stirring frequently, about 2 minutes.

Pour the heavy cream into the skillet along with 1/2 cup of grated Parmesan cheese. Season with salt, pepper, and a pinch of nutmeg if using. Allow it to simmer for 3-4 minutes until slightly thickened.

Return the meatballs to the skillet, spoon the creamy sauce over them, cover, and simmer on low heat for 10 minutes or until the meatballs are fully cooked through.

Serve the meatballs hot, garnished with extra parsley and Parmesan if desired.