In a small bowl combine, cornstarch, soy sauce, oyster sauce then add chicken, mix well. Set in the fridge.
In another bowl combine the soy sauce, sherry, water, chicken stock, oyster sauce, cornstarch, and brown sugar. Set aside.
Heat up the Wok with about 2 tablespoon of oil, and then add chicken let it rest for about 30 seconds before stirring. Cook for 4-5 minutes or until chicken has been fully cooked; remove and keep warm.
Stir the onion, then add garlic, ginger chilli sauce and continue stirring for another 2 -3 minutes.
Add the combined sauce, and basil, stir for about 2 minutes, followed by the , cashews, chicken and green onions. Stir for about 1 minute.
Remove and serve over rice.