Turn Instant Pot to Saute mode. Add sausage and chopped onions. Cook, breaking meat apart and stirring frequently, until browned (about 4-5 minutes). Add garlic & continue cooking until fragrant, about 1-2 minutes. Drain excess grease.
Add broth and scrape the bottom of the pot to loosen any browned bits (aka deglaze). Turn off the Saute mode.
Stir in potatoes. Make sure the contents don’t exceed the Max Fill line on the inner liner.
Close and seal the lid and set the steam valve to Sealing.
Select Manual High-Pressure setting and set the timer to 5 minutes. The pot will take 5-7 minutes to come to pressure.
When the cook cycle ends, allow pressure to release naturally for 10 minutes, then quick release any remaining pressure.
Carefully open the lid when the pressure has fully released. Add chopped kale and stir until wilted.
Add Half & Half and stir until heated through (1-2 minutes).
Season with salt and pepper to taste.
Serve with freshly grated Parmesan cheese if desired.