Turn your Instant Pot to the saute setting. (See your manufacturer's guide for detailed instructions on how to use your instant pot.)
Heat the olive oil in the Instant Pot, then add the sausage and brown for 3 minutes until it's no longer pink, breaking up with a wooden spoon.
Stir in the onion and garlic and cook for another 3 minutes until the onion softens and becomes translucent.
Stir in the red pepper flakes, Italian seasoning, salt and pepper. Add the cubed potatoes and the chicken broth. Give it a stir.
Close the lid (follow the manufacturer's guide for instructions on how to close the instant pot lid). Set the Instant Pot to the Manual setting and set the timer to 5 minutes.
Once the Instant Pot cycle is complete, wait until the natural release cycle is complete, should take about 10 minutes. Follow the manufacturer's guide for quick release, if in a rush. Carefully unlock and remove the lid from the instant pot.
At this point you can adjust the salt and pepper if necessary. Add the chopped kale and set the Instant Pot to the saute setting again. Cook for two more minutes uncovered, until the kale cooks a bit. Stir in the half and half or heavy cream.
Turn off the Instant Pot, by pressing the cancel button. Serve the soup warm garnished with Parmesan cheese or bacon bits if preferred.