Preheat your oven to 350°F (175°C).
In a large pot of boiling salted water, cook the egg noodles according to the package instructions until al dente. Drain and set aside.
In a large skillet, heat olive oil over medium heat. Combine ground beef and ground pork in a mixing bowl, and add breadcrumbs, chopped parsley, grated onion, minced garlic, egg, salt, black pepper, allspice, and nutmeg. Mix well to form meatballs (about 1 inch in size).
Add the meatballs to the skillet and cook until browned on all sides, about 10 minutes. Remove the meatballs and set aside.
In the same skillet, add beef broth, heavy cream, and sour cream. Stir to combine and bring to a simmer. Let it cook for about 5 minutes until slightly thickened.
In the baking dish, combine the cooked noodles, meatballs, and creamy mixture. Stir well to combine and ensure everything is evenly distributed.
Sprinkle shredded mozzarella and grated Parmesan cheese over the top of the noodle and meatball mixture.
Bake in the preheated oven for about 25-30 minutes, or until the cheese is melted and bubbly and the top is slightly golden.
Remove from the oven and let it sit for 5 minutes before serving. Garnish with chopped chives if desired.