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 pasta and return meatballs to the pot. Reduce heat to medium and simmer for 15-18 minutes, stirring occasionally, until pasta is tender and meatballs are cooked through.
Remove from heat and let stand for 3-5 minutes to allow sauce to thicken.
Serve topped with shredded mozzarella and fresh basil.