First, you'll want to estimate the width of your sweet potatoes to come up with an approximate cooking time. If you have a lot of potatoes, use the cooking time for the largest potato. (It will be about 20 - 45 minutes.)
2 - 8 sweet potatoes
Wash the potatoes, then poke them with a fork a few times.
Pour 1 cup of water into the bottom of the pot. (Use 1 cup for a 3 or 6-quart Instant Pot or 1 ½ cups for an 8-quart Instant Pot.)
1 cup water
Then, place a trivet, steamer basket, or sling on top of the water. If you don't have a trivet, you can use mason jar rings, biscuit cutters, or make little logs out of aluminum foil - you just want to keep the potatoes out of the water.
Next, arrange the sweet potatoes on top of the trivet, stacking them on top of each other if needed. You can load the Instant Pot all the way to the top, as long as the lid can close.
Place the lid on your Instant Pot and set the valve to the Sealing position.
Pressure Cook the sweet potatoes at High Pressure for the time you selected based on the size of your sweet potatoes. (Remember, it will also take 10-15 minutes for the Instant Pot to come to pressure.)
When the cooking cycle completes, allow pressure to Naturally Release for about 10 minutes, then carefully Quick Release the remaining pressure.
Carefully open the lid and allow the potatoes to cool for about 10 minutes before removing them from the Instant Pot. They will be really hot.
Once the potatoes have cooled enough to touch, remove the sweet potato flesh from the skins and use it in your favorite sweet potato recipes. You can also just slice open the potatoes and serve them with a little butter, a sprinkle of brown sugar, or nut butter on top.