Cook potato, corn, celery, onion, broth, salt, and pepper in the Instant Pot on high for 6 minutes.
While the Instant Pot comes to pressure, melt butter and flour together in a saucepan on medium heat. Slowly add in the milk and stir until the mixture is thickened. Turn off the heat and add the cheese, stirring to melt.
Release the pressure from the Instant Pot. Stir in the milk mixture and bacon.
Notes
Skip the bacon and use vegetable broth to make vegetarian.
Use a gluten-free flour blend or rice flour for thickening to make this gluten-free.
We like the look of peeled potatoes in this soup, but you don't need to peel if you're short on time.