Bring a medium saucepan of water to the boil for the noodles. Halve the carrot lengthwise and thinly slice on an angle. Cut the spring onion into 3cm lengths. Thinly slice the pak choy, keeping the stems and leaves separate.
Step 2 — Prep sauce
Combine the oyster sauce, sambal oelek, 1 tsp white vinegar and 2 tbs water in a bowl. Season with pepper.
Step 3 — Prep and cook chicken
Thinly slice the chicken into strips. Heat 2 tsp oil in a medium deep frypan over high heat. Stir-fry the chicken for 3-4 mins until golden and cooked through. Remove from the pan.
Step 4 — Stir-fry vegetables
Heat 1 tsp oil in the same pan over high heat. Stir-fry the carrot and spring onion for 2-3 mins until almost tender. Add the pak choy stems and stir-fry for a further 2 mins or until tender.
Step 5 — Cook noodles
Meanwhile, cook the noodles in the pan of boiling water for 2 mins or until tender. Drain, then rinse under hot water to prevent the noodles from sticking.
Step 6 — Toss noodles and serve
Add the chicken, sauce, pak choy leaves and noodles to the vegetables and toss to combine. Taste, then season with salt and pepper. Divide the noodle stir-fry among bowls and scatter with the peanuts to serve.