In a skillet, cook ground beef and onion over medium-high heat until browned, about 5 minutes. Add garlic, salt, basil and parsley and cook 1 minute more.
Transfer meat mixture to a 4-quart or larger slow cooker. Add diced tomatoes, pasta sauce and chicken broth. Stir to combine.
Cover and cook on LOW for 6 hours or HIGH for 3 hours.
Increase heat to HIGH. Add dry pasta and stir to submerge in sauce. Cover and cook 15 minutes, then check pasta for desired tenderness. Cook longer if needed, up to 30 minutes total.
Sprinkle mozzarella over top, cover and let sit 3-5 minutes until melted. Serve warm.