Add the 6 medium potatoes (32 oz / 907g), 1 tbsp. (0. 1 oz / 3g) chopped chives, 0. 5 tsp. (0. 1 oz / 3g) kosher salt, and 0. 25 tsp. (0. 04 oz / 1g) ground black pepper directly into the Instant Pot.
Pour in the 1 cup (8 fl oz / 240g) of chicken broth and stir gently to combine. Close and securely lock the lid in place.
Select the MANUAL setting and cook at HIGH pressure for exactly 5 minutes.
Once the pressure cooking cycle is complete, immediately select CANCEL and perform a Quick Release to vent the steam. Carefully unlock and remove the lid.
Transfer the cooked potatoes using a slotted spoon to a baking sheet or a 9x13-inch (approx. 23x33cm) casserole dish.
Preheat your oven to the broil setting. Returning to the Instant Pot, whisk the 0. 33 cup (2. 7 oz / 77g) sour cream, 0. 33 cup (2. 7 fl oz / 79g) milk, and 2 tbsp. (0. 7 oz / 20g) potato starch into the remaining hot cooking liquid.
Select the SAUTÉ function on the Instant Pot and cook the dairy mixture for 1 minute, whisking constantly until it has visibly thickened into a rich sauce.
Pour this thickened mixture evenly over the plated potatoes and gently stir to coat them.
Sprinkle the top with 0. 25 tsp. (0. 02 oz / 0. 5g) paprika and place the dish under the oven broiler for 3 to 5 minutes until you achieve a beautiful, bubbly, browned top.