In a bowl, mix ground chicken, egg, breadcrumbs, garlic, Parmesan, Italian seasoning, salt, and pepper. Roll into small meatballs, about 1 inch in diameter.
Heat 1 tbsp olive oil in a large skillet over medium heat. Add meatballs and cook for 6–8 minutes, turning occasionally, until browned on all sides (they don’t need to be fully cooked through yet). Remove from the skillet and set aside.
In the same skillet, add another tablespoon of olive oil. Sauté the chopped onion until soft, about 3 minutes. Add garlic and cook for 1 more minute. Stir in the orzo and toast it for 1–2 minutes until lightly golden.
Pour in the chicken broth and dried thyme (or Italian seasoning). Return the meatballs to the pan and bring everything to a gentle simmer. Cover and cook for about 12–15 minutes, stirring occasionally, until the orzo is tender and the meatballs are fully cooked.
Stir in milk or cream if using, and add grated Parmesan cheese. Cook uncovered for a couple more minutes to let the sauce thicken. Season with salt and pepper to taste.
Sprinkle with fresh parsley or basil before serving. Serve warm straight from the skillet.