Set the instant pot on saute function and saute your bacon until golden brown, about 5-7 minutes
Remove from the pan and deglaze with chicken stock
Add potatoes to the pot and give everything a good stir being sure to scrape those bacon bits from the bottom of the pot
Cover the instant pot and cook the potatoes on high pressure for 6 minutes, quick release
Once the potatoes are fork-tender drain them and reserve that chicken stock for later
Mash the potatoes and set them aside
Put the instant pot back on saute and saute the onions and garlic in butter for 2 minutes until fragrant
Add flour and cook for one minute until flour is dissolved
Add chicken stock back to the pot and whisk until smooth and roux has dissolved
While keeping the instant pot on the saute function, slowly add back in the mashed potatoes to the broth one scoop at a time, whisking as you go
Once the potatoes are incorporated into the broth and everything is smooth add milk, cheese, and sour cream, mix well then season to taste
Serve soup warm and top with crumbled bacon, chives, and a scoop of sour cream