Turn on the Sauté setting. When the pot is hot, add the oil.
Add the chicken pieces and cook until the chicken is mostly done, but not fully cooked.
Add the orange juice, soy sauce, rice vinegar, ginger, garlic, orange zest brown sugar, tomato ketchup, and sriracha. Stir well.
If Making Rice: Add rack and pan of rice / water to the pot (see notes).
Close the lid and turn the steam release valve to the Sealing position (if not self-sealing).
Press the Pressure Cook/Manual button or dial, then the +/- button or dial to select 4 minutes. High Pressure. The pot will take a few minutes to come to pressure.
When the cook cycle has finished, turn off the pot and let it sit undisturbed for 10 minutes (10 minute natural release). Then turn the steam release valve to the Venting position to release any remaining steam/pressure.
Open the lid and press the Cancel button.
If Making Rice: Remove the pan of rice and the rack, using a pot holder, very carefully as it is very hot. Set aside.
Press the Sauté button.
In a bowl whisk together cornstarch and water until completely dissolved to make a smooth cornstarch slurry.
Once the sauce starts to bubble, slowly pour in the cornstarch slurry while stirring the sauce.
Allow to bubble and cook for 1-2 minutes or until the sauce thickens.
Select the Cancel button to turn off the pot.
Garnish with spring onions and sesame seeds.
Serve hot with rice.