In a bowl, combine ground turkey, breadcrumbs, egg, Parmesan, salt, and pepper. Mix gently and form into 1-inch meatballs (about 20-24 meatballs).
Heat olive oil in a large pot or Dutch oven over medium-high heat. Brown meatballs on all sides, about 5 minutes total. They don't need to be cooked through. Remove and set aside.
In the same pot, add diced onion and cook for 3 minutes until softened. Add garlic and Italian seasoning, cooking for 1 more minute.
Pour in marinara sauce and broth, stirring to combine. Bring to a boil.
Add the pasta and return the meatballs to the pot. Reduce heat to medium and simmer for 15 to 18 minutes, stirring occasionally, until the pasta is tender and the turkey meatballs reach 165°F (74°C) in the center.
Remove from heat and let stand for 3-5 minutes to allow sauce to thicken.
Serve topped with shredded mozzarella and fresh basil.