Turn your Instant Pot to saute. Once it reads "HOT," add in 1/2 -1 tablespoon oil and let heat for 1 minute.
Add in chicken and saute until JUST browned--about 2-3 minutes.
Add in orange juice, orange zest, brown sugar, soy sauce, rice wine vinegar, ginger and garlic to instant pot.
Close the pot, and set the valve to seal.
Set the manual button to "high pressure" and set the timer for 7 minutes. Note: you will have to FIRST turn off the instant pot from the saute function.
Let naturally release for 5 minutes. Then do a quick release.
Turn Instant Pot back to saute. Make a cornstarch slurry by mixing cornstarch with 2 tablespoons water until fully combined. Add cornstarch slurry to pressure cooker and stir and boil for 2-3 minutes.
Serve with steamed rice, cauliflower rice and scallions if desired.