In a large mixing bowl, combine ground chicken, breadcrumbs, grated Parmesan, chopped parsley, minced garlic, dried oregano, egg, salt, and pepper.
Mix the ingredients until well combined. If the mixture is too wet, you can add more breadcrumbs.
Shape the mixture into meatballs, about 1 inch in diameter.
In a large skillet, heat olive oil over medium heat. Add the chicken meatballs and cook until browned on all sides and cooked through (internal temperature of 165°F or 74°C), about 10-12 minutes.
In a separate saucepan, heat olive oil over medium heat. Add chopped onion and cook until softened.
Add minced garlic and cook for an additional 1-2 minutes until fragrant.
Pour in the crushed tomatoes and add dried basil, dried oregano, salt, and pepper. If the sauce is too acidic, add a pinch of sugar.
Bring the sauce to a simmer and let it cook for 15-20 minutes, allowing the flavors to meld.
Once the chicken meatballs and tomato sauce are ready, gently combine them.
Serve the chicken meatballs and tomato sauce over cooked spaghetti.
Garnish with grated Parmesan cheese and fresh basil or parsley.