Add 1 cup of water to Instant Pot. Push saute' button and bring to boil. (about 2-3 minutes). Leave the metal wire rack in the pot (that came with your Instant Pot) so the springform pan will rest on top of it.
Take a piece of foil and make a 8 inch wide by 2 foot long sling so you can easily place the pan in the pot and also cover the top of the cake while it's cooking. Turn off the saute' option, and place the cake into the pot, using the foil as handles. Fold the foil over the top of the springform pan to cover it.
Cook the cake on normal high pressure for 35 minutes. After 35 minutes cook time, leave the cake in the pot to cool down for 20 additional minutes. Remove from pot and set aside. (You may want to use the corner of a paper towel to dab up any slight moisture that may have accumulated).
While the cheesecake is cooking, warm up the 1/2 cup of sour cream and 2 tbsp of sugar on the stovetop until the sugar is just dissolved. (we're just trying to warm it up a bit, not cook it).
Add the warmed sour cream mixture to the top of the just removed cheesecake. Turn on oven to low broil and place the cake under it until it just starts to thicken. Do not brown the top.
Remove from the oven, let it cool for 30 minutes, then pop it in the fridge uncovered for at least 12 hours. Run a knife around edge of cake before releasing from pan. Add choice of toppings.