1.Place noodles in a large heatproof bowl; cover with boiling water. Separate noodles with a fork; drain.
2.Heat half the oil in a wok; stir-fry chicken, in batches, over medium heat for about 1-3 minutes, or until browned lightly.
3.Heat remaining oil in wok; stir-fry onion, garlic, ginger and capsicum for about 2 minutes, or until onion is just tender.
4.Return chicken to wok with sugar, sauces and choy sum; stir-fry for a further 2-3 minutes, or until chicken is cooked through and choy sum is wilted.
5.Add noodles and half of the nuts; toss gently until heated through. Serve topped with remaining nuts.