Add olive oil to the Instant Pot. Using the display panel select the SAUTE function.
When oil gets hot, brown the chicken on both sides, 3-4 minutes per side. Meat will not be cooked through. Do not crowd the pot–you may have to work in batches. Transfer browned meat to a shallow dish and cover loosely with foil.
Add onion to the pot and saute until soft, 3-4 minutes. Add garlic and cook for 1-2 minutes more.
Add soy sauce, ketchup and red pepper flakes to the pot and deglaze by using a wooden spoon to scrape the brown bits from the bottom of the pot.
Put the chicken back into to the pot, turning once to coat.
Turn the pot off by selecting CANCEL, then secure the lid, making sure the vent is closed.
Using the display panel select the MANUAL or PRESSURE COOK function*. Use the +/- keys and program the Instant Pot for 5 minutes.
When the time is up, let the pressure naturally release for 5 minutes, then quick-release the remaining pressure.
Carefully remove the meat from the pot to a cutting board and chop into bite-sized pieces.
Add honey and sesame oil to the pot and stir to combine.
In a small bowl mix together 1/4 cup of pot liquid and cornstarch. Stir into the pot until thickened.
Add chicken back to the pot and stir to coat. Adjust seasonings.
Serve hot over rice, noodles or zoodles, garnished with scallions and sesame seeds.
*The MANUAL and PRESSURE COOK buttons are interchangeable.