Turn your Instant Pot to Sauté mode. Once it is heated up, add the coconut oil and let it melt.
Once the coconut oil is melted, slowly add the popcorn kernels, then stir with a heatproof silicone spatula to coat the kernels with the oil.
When you hear the kernels start to sizzle, cover the Instant Pot with a glass lid. Cook on Sauté for 5 to 6 minutes, just until about ⅔ of the kernels have popped.
Then hit Cancel to stop the Sauté mode, and allow the kernels to continue popping. Once you no longer hear kernels popping, remove the lid and carefully scoop out the popcorn to a serving bowl with a wooden spoon or using the heatproof spatula.
Optional: sprinkle additional mix-ins, such as two tablespoons of melted butter, flaky finishing salt, paprika, garlic salt, or nutritional yeast. Toss the popcorn together to coat the popcorn with your optional mix-ins.