To make this, simply build layers in the Ninja Foodi.
Place the meatballs as the base layer and stack as needed. Cover with the beef stock.
Add the spaghetti on the tops and simply press down into the beef stock. Do not stir this in.
Cover with the jar of sauce.
Select Pressure on Ninja Foodi. Set to High for 8 minutes.
Quick release the pressure once cooking is completed
Open and stir the spaghetti. Let rest for 5 minutes
Sprinkle with Parmesan cheese and serve immediately.