1. Make the Meatballs: In a medium bowl, combine the ground chicken, breadcrumbs, egg, Italian seasoning, garlic, onion powder, salt, and Parmesan cheese. Mix with clean hands or a fork until well combined.
2. Shape and Cook: Roll the mixture into 10 large or 18 small meatballs. Heat the olive oil in a large skillet over medium-high heat. Add the meatballs and cook until browned on all sides and cooked through. Remove the meatballs from the skillet and set aside.
3. Make the Sauce: In the same skillet, melt the butter over medium-high heat. Add the garlic and cook until fragrant. Whisk in the flour to form a paste.
4. Add Liquids and Cheese: Gradually whisk in the chicken broth and heavy cream until the sauce is smooth. Stir in the Parmesan cheese, sun-dried tomatoes, and Italian seasoning. Season with additional salt and pepper, if needed.
5. Simmer and Thicken: Bring the sauce to a simmer and cook until thickened, stirring occasionally.

Combine and Serve: Return the cooked meatballs to the skillet with the sauce. Reduce the heat to medium-low and simmer for 5 minutes, or until the meatballs are heated through. Garnish with fresh basil leaves and serve over your choice of mashed potatoes, pasta, or rice.