Turn your Instant Pot on to the saute setting, and heat up the sesame oil.
Saute the chicken in 2 batches, turning to brown on each side, but not cook all the way through, about 5-7 minutes in total.
Meanwhile, combine the hoisin sauce with the rice vinegar, tamari, garlic, ginger, red pepper, brown sugar and chili oil in a small bowl.
Press cancel on the Instant Pot, then stir the chicken and sauce till combined.
Set the Instant Pot to Manual and cook at high pressure for 8 minutes.
Once done cooking, use quick release to depressurize. Press cancel and return pot to Saute function. While simmering, whisk in the corn starch or arrowroot powder and continue to cook 1-2 more minutes until the sauce is thickened.
Press cancel and serve with rice and veggies.