Turn the Instant Pot on sauté, add the chicken broth and polenta and whisk together.
As soon as it starts to boil, place and seal the lid and set your Instant Pot on high pressure for 7 minutes. Allow it to release pressure naturally when done.
When you open the lid there will be some excess water in it. Using your whisk, blend in the butter, cheese, and half and half. The polenta will thicken as you whisk it all together. Allow it to rest for a little longer and then serve warm.