Mix together the orange juice, tamari soy sauce, cider vinegar, sesame oil, sugar, garlic, ginger, chilli flakes and salt in a bowl and set aside.
Add the chicken and the sauce into the Instant Pot insert.
Cover your Instant Pot, set the vent to 'sealing,' select the manual or pressure cook button (dependent upon IP model), select high pressure and set the timer to 5 mins.
When done allow to NPR for 10 mins then QPR and open the lid.
Mix the cornflour with 1 tbsp of water and make a lump free paste.
Select the sauté function and add the cornflour paste, mix and sauté for about 3 mins until thickened and switch off the heat.
Garnish with spring onion and toasted sesame seeds before serving.