To start, put the Instant Pot on saute mode. When it's heated up you can spray the bottom with the cooking spray and add the onions and garlic. They need to cook for about 3 minutes until softened and translucent.
Next, add the sausage and cook while stirring for about 2 minutes. We will add in the chicken stock at this point as well as the marinara, water, salt, pepper, and noodles.
After all the ingredients are added and stirred up you can put on the lid and lock it into place. Make sure the pressure value is closed and set the IP to cook on high pressure for 3 minutes.