Add your diced potatoes, diced onions, chicken broth, seasonings, and butter to your Instant Pot.
Place the lid on top, lock and set the valve to sealing.
Set the pressure for 5 minutes
Do a quick release to release the pressure.
In a small mixing bowl whisk the heavy cream, sour cream, and the corn starch together.
Stir into the soup.
Mix in the sharp cheddar cheese
Press the saute button and cook the soup (while stirring) until the soup thickens.
Use an immersion blender to blend the soup to make a smooth and creamier soup.