Set your instant pot to sauté mode. Once hot add in your butter (for healthier alternative, cooking spray will suffice). Add your onion and sauté for 3-4 minutes until it begins to soften.
Once your onion has softened, add in your garlic. Sauté for about a minute to release the flavors of the garlic.
Press cancel on your instant pot. Add in your potatoes, thyme, nutmeg, broth, salt and pepper.
Close and seal the lid on your instant pot, and close the valve. Select pressure cook on high for 4 minutes. Once the time is done cooking, naturally release 45 minutes, then do a manual release by opening the valve.
Press cancel on your instant pot, then sauté mode. In a separate bowl mix together your milk and corn starch. Once completely mixed together, add to your instant pot. Carefully stir the corn starch mixture making sure not to mash any potatoes. Keeping it chunky. Allow it to sauté for about three minutes to thicken up.
Mix your sour cream. Once fully incorporated, press cancel on your instant pot.
Christina's Notes
Thicker soup: Use less liquid or blend the soup for a longer time.
Creamy soup: For a creamier soup, you can add more heavy cream or milk. You can also add some cream cheese!
Spicier: Add a pinch of cayenne pepper or a dash of hot sauce to add some spice.
Bacon: Cook the bacon in the oven to make a potato soup loaded with bacon.
Healthier: Use low-fat milk and a reduced-fat sour cream. Omit any use of bacon fat as well.
Smoother Soup: To make a less chunky soup, you have a couple options. You can place the soup in a blender, use an immersion blender or you can use a potato masher to mash everything together.