Using a paper towel, pat chicken dry, cut the chicken into 1-2 inch chunks, then season with salt and pepper.
Heat up your pressure cooker: press Sauté. Wait for the Instant Pot indicator to read HOT.
Add the oil to the hot Instant Pot, add the chicken and sauté for 2-3 minutes, stirring frequently so as not to allow sticking. Cook until it just starts to get golden.
Add 1/4 cup orange juice to the pot and use a wooden spoon to scrape the browned bits from the bottom.
Add the Sauce ingredients to the pot: remaining 3/4 cups of orange juice, minced garlic, ginger, coconut aminos, coconut sugar, rice wine, and orange zest.
Stir gently until all the ingredients are combined and coated in sauce.
Close lid, taking care that the vent is closed. Select Manual, and select 5 minutes on High Pressure.
Use a 10 minute Natural Release. Release the remaining pressure by opening the vent. Let the Instant Pot finish releasing steam before opening the lid.
Select again the Sauté function. In a medium bowl combine arrowroot with the orange juice for the Slurry, whisk until all combined with no lumps.
Add the Slurry mixture to the Instant Pot and gently stir to combine. Cook on Sauté function for a few more minutes, stirring gently, until the sauce thickens. Simmer for 2-3 minutes. If you want the sauce even thicker, mix one more tablespoon of arrowroot with orange juice and add it to the pot.
Let the Orange Chicken stand for 5-7 minutes, the sauce will thicken more.
Serve and garnish with fresh chopped green onions and extra orange zest.