Prepare Sweet Potatoes - Wash, peel, and cut the potatoes into 1-inch pieces. Add the sweet potatoes and water to the Instant Pot. Make sure that the release valve is in the "Sealing" position. Place the lid on, turn and lock.

Pressure Cook - Press the "Manual" button on the Instant Pot on high pressure, and then set the timer to 10 minutes using the "+" or "-" controls.It will take about 10 to 15 minutes for the pot to heat and build up pressure. You will see some steam release from the lid, and then the time will start on the display. Once the cooking time is complete, carefully quick-release the pressure from the pot by turning the steam release handle on the lid to the "Venting" position and then remove the cover.

Drain Liquid - Drain the potatoes and transfer them to a large bowl.

Mash Sweet Potatoes - Add butter, cinnamon, nutmeg, and salt to the potatoes. Mash using a potato masher until a smooth puree is created with some small chunks. Adjust seasonings as desired.