Turn instant pot to saute mode and cook bacon until crisp. You may need to do this in 2 batches. Remove bacon and all grease except for about 1 Tablespoon. Drain bacon on a paper towel lined plate.
Saute onion for about 2 minutes, add garlic and cook 1 minute more.
Cancel saute mode and add a bit of broth. Scrape bottom to remove any browned bits. Add potatoes, corn, seasonings, remaining broth and stir.
Put lid on and seal. Turn Instant Pot to high pressure for 10 minutes. Allow to natural release for 2 minutes, then quick release the rest.
Remove lid and cancel pressure cook mode. Using a hand blender, blend a bit of the soup. Alternately, remove 3 cups of soup and blend in a blender, then return to the soup.
Add ½ cooked bacon to soup. Whisk flour and cream together. Set Instant Pot to saute mode. Once soup is bubbling, add cream mixture. Allow to cook for 1-2 minutes until thick.
Garnish with reserved bacon and green onion.