Heat oil in a pan. Coat the chicken pieces with tempura flour and fry until slightly cooked. Remove and set aside.

Pour out excess oil, leaving a little in the pan. Add the onion and bell peppers, stir-frying until the onion is translucent. Add the fried chicken and water chestnuts, stirring to combine.

Season with sugar, soy sauce, and oyster sauce. Stir well, then add the Chinese cooking wine and mix. Add the green onions, fried dried chilies, and cashew nuts, stirring briefly to combine. Turn off the heat.