Add peanuts to the Instant Pot. Add enough water to cover the peanuts. Add salt and Taco seasoning.
Put a trivet on top of the peanuts and a bowl or plate on top to keep peanuts from floating up. (I used my Instant Pot Pyrex bowl as a weight.)
Close the lid and turn the valve to a Sealing position. Press the "Pressure Cook" or "Manual" button and set the time to 1 hour on High pressure.
When it's done cooking, quick release (QR) the steam. Drain the boiled peanuts and serve.
*If not using Taco seasoning, increase the amount of salt to 1/3 cup, as Taco seasoning contains some salt.**Boiled peanuts will keep in a refrigerator for 1 week. You can also freeze them in a ziploc bags for up to 6 months.