Add water to the bottom of an Instant Pot®) or pressure cooker. Place a rack or steamer basket over the water (water level should be lower than the rack.)
Wash and dry potatoes. With a fork or sharp kitchen knife, pierce each potato 2 or 3 times.
Rub each potato with a little oil (just enough to lightly coat) and salt generously.
Place the potatoes in the steamer basket. Close and lock the lid. Set pressure cook setting to high. Set timer for 16 minutes. If your potatoes are larger than 14 ounces, pressure cook for 20 minutes. Allow 10 minutes for pressure to build.
Release pressure using the natural-release method according to manufacturer's instructions for best results, 10 to 40 minutes. Unlock and remove the lid.