To help the chicken brown, dry the chicken breasts with paper towel to remove all moisture. Cut into 1- inch chunks.
Heat up the Instant Pot. Press the Saute button, and keep pressing the button to toggle to MORE on the indicator. MORE function means that the food will be saute'd over medium-high heat. Wait for the display to read HOT.
Add the oil to the Instant Pot. When hot, add the chicken and saute for 3-4 minutes. Stir the chicken constantly so the chicken does not stick to the bottom of the pan. If you see excess moisture at the bottom of the Instant Pot, use a spoon to remove the excess moisture and discard it. Cook until the chicken is golden. If you have any bits that have stuck to the bottom of the pan, de-glaze the pan by pouring in 1/4 cup of the orange juice and stirring until the bits have released.
Add the ginger, garlic, orange juice,water, red pepper flakes, vinegar, honey, brown sugar, soy sauce and sriracha to the Instant Pot. Stir to combine and coat the chicken.
Close the lid and select the Pressure Cooker function. Set on HIGH for 5 minutes. Make sure the Keep Warm light is ON and the Vent is CLOSED.
Use the 10 Minute Natural Release method. Turn off the heat, carefully open the vent and vent the remaining pressure. Remove the lid.
Again, select the Saute' function. Select LOW.
In a small bowl, mix the cornstarch with 2 tablespoons water until smooth. Add to the Instant Pot and Saute' until the sauce is thickened. If the sauce is too thin, mix another tablespoon of cornstarch with a tablespoon of water and add it to the pot. Turn off the heat and allow to stand for 5 minutes to continue thickening.
Transfer to a serving dish and garnish with green onion and orange slices. Serve with rice or a grain like farro for a complete meal.