Power on your 6- or 8-quart Instant Pot and select the 'Sauté' function. Adjust the settings to a higher sauté temperature and wait for 2 to 3 minutes until the pot reaches the desired heat level. Have a popcorn bowl ready on the side.
Add the coconut oil and wait until it melts. Add 2 to 3 popcorn kernels to the pot. Once they pop, add the rest of the kernels and stir with a wooden spoon to ensure the popcorn is coated with oil.
Cover the pot with a glass lid, leaving the lid slightly ajar. You can use the Instant Pot glass lid (sold as an accessory) or one from another pot. Cook until the popping of the popcorn has begun to slow, with several seconds between each pop. Press the 'Cancel' button to turn off the heat and allow the remaining kernels to pop with the residual heat. Once all kernels have popped, transfer the popcorn to a bowl and sprinkle it with sea salt.