Heat half of the sesame oil in a wok over a moderate heat and stir-fry the onion and garlic for 2-3 minutes.
Add the peppers and bamboo shoots and continue to stir-fry for a further 2-3 minutes. Add the diced chicken, stir-fry for 4-5 minutes then add the sweet and sour sauce. Bring to a simmer and cook for a further 5 minutes until the meat is cooked through with no pink showing.
Re-heat the noodles if necessary, then toss with the sesame oil to coat evenly. Spoon the noodles onto serving plates then spoon the sweet and sour sauce next to them. Serve immediately.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home and view the full Food safety at home video.