Pour 1.5 c of water into your pressure cooker and put a trivet in the middle of your pot.
In a bowl that is oven/pressure cooker safe add your frozen corn, 1 tbsp water, butter and sugar. Place bowl on trivet. (use foil sling or trivet with handles so you can lift it back out)
Close your lid and steam valve and set to pressure high for 4 minutes. Do a quick release when done.
Remove bowl and trivet, drain water inside the pot. Dump buttery corn mixture into your inner pot and set to saute, low.
Add shredded cheddar cheese and cream cheese (cut into small blocks so it melts easier) and stir slowly until cheeses melt. Add milk to thin out, can add more or less depending on how thick you like it.
Then turn pot off, transfer to a serving dish and serve!