To the same skillet you cooked the meatballs, add butter. Once melted, add diced onions and cook for 2–3 minutes until softened. Stir in garlic and cook for 1 additional minute.
Slowly pour in the chicken broth, scraping up any browned bits from the bottom of the pan for extra flavor.
Add the sun-dried tomatoes, cream cheese, salt, and pepper. Cook, stirring, until the cream cheese is completely melted, about 5 minutes.
Stir in the orzo pasta, making sure it's well coated. Pour in the heavy cream and stir until combined. Bring to a gentle simmer.
Cover the pan and reduce heat to medium-low. Let the orzo simmer for 12–15 minutes, stirring occasionally to prevent it from sticking to the pan.
In the last 5 minutes of cooking, add parmesan, cheddar, and Monterey Jack cheese. Stir to combine until fully melted.
Return the cooked meatballs to the skillet and gently fold them into the sauce. Continue cooking until the orzo is al dente and the meatballs are warmed through.
Remove the skillet from the heat and let the dish rest for 5 minutes to allow the sauce to thicken.
Garnish with parsley and sun-dried tomatoes before serving.