Press saute button on the Instant Pot and add the oil to the pot. Next, add the onion, carrots and celery and saute for 5 minutes.
Add the sausage and brown for about 5 minutes. Add the remaining ingredients and stir.
Put on the lid and lock . Adjust setting to manual pressure cook for 25 minutes.
After cook time is complete, let the pressure naturally release for 10 minutes and finish with quick release. Ladle into bowls, top with cheese, and serve.