Cut the chicken into 1-inch cubes, and toss the cubes with cornstarch to coat. Prepare all the herbs and vegetables.
Set the Instant Pot on Sauté. Pour in the sesame oil. Add the onion, garlic, and ginger. Sauté for 2 minutes, then add the chicken pieces. Stir and brown for 3-5 minutes, until the chicken pieces are golden on most sides. Scrape the bottom of the pot with a metal spatula to make sure nothing is stuck to the bottom. (This can cause the "Burn Notice" on your IP.)
Add the brown sugar, soy sauce, sherry, chili garlic sauce, and 2 tablespoons water to the Instant Pot. Stir well to coat the chicken.
Cover and seal the pot. Set on Pressure Cook High for 3 minutes. Turn off the pressure cooker, and perform a Quick Release. Once the steam valve button drops, and it is safe to open, remove the lid. Stir the sesame chicken and sprinkle with sesame seeds and scallions. Serve warm with rice, quinoa, or with steamed vegetables.
Instant Pot Issues: Electric Pressure cookers get a little touchy when there are bits of flour or cornstarch stuck to the bottom of the pot. This can set off the "Burn Notice" which stops the cooking process. Make sure to scrape the bottom of the pot after searing the chicken, so the IP will cook all the way through.