In your Instant Pot, put your heavy whipping cream, pesto, and chicken broth. Then add the rotini.
Use a spoon to make sure that the rotini is covered in the liquid.
Add the lid onto the Instant Pot and press MANUAL or HIGH for 6 minutes. When the cooking cycle is complete, perform a Quick Release.
Open the lid of the Instant Pot, and add the parmesan ¼ cup at a time, stirring in between.