Add all the ingredients listed under the "Cook on High Pressure" to the pot. Make sure you don't go over the inner Max line of your pot
Stir to combine.
Close and lock the lid, point knob to sealed.
Press High Pressure and input 10 minutes. It will take the Instant Pot to come to pressure about 15-20 minutes, due to the high volume of the soup.
Once done cooking, do a 10-minute Natural Pressure Release, after which, carefully release the remaining pressure by moving the knob to the Vent position.
Lift the lid and use a potato masher to mash some of the potatoes.
In a cup whisk cornstarch and cream until well combined and smooth.
Select Sauté, and whisk in cream mixture until fully combined. Simmer for a few minutes, until the soup thickens. If the soup is too thick, add more cream or broth, and simmer.
Stir in sour cream.
Turn off the pressure cooker and stir in cheddar cheese until melted.
Serve hot garnished with bacon, cheese, and green onions.