Add the chicken broth to the bottom of your Instant Pot. Place the steamer basket or trivet on top of the broth and add your potatoes. Sprinkle with half the salt. Put the lid on the pot and turn to sealed. Set the manual timer to 8 minutes.

While potatoes cook, melt butter in a small sauce pan. Once melted, add the milk. Cook over low heat until warm.

When Instant Pot beeps, do a quick release and release the pressure. Remove potatoes from the pot and add to a large mixing bowl. Add half of the butter and milk combination and the sour cream. Using a hand mixer, mix on medium-high speed until smooth and creamy. Add additional milk/butter mixture until you get your desired consistency. I used about 3/4 of the mixture.