Combine all sauce ingredients in a small bowl and set aside.
In a separate bowl, toss the chicken with 1 tablespoon of the sauce and pepper.
Heat oil in a large pan over high heat. Cook the chicken for 1–2 minutes until just done.
Add garlic and the white parts of the spring onions. Stir-fry for 30 seconds until fragrant.
Add cabbage and carrot, cooking for 2–3 minutes until slightly tender but still crisp.
Add the noodles, remaining sauce, and green spring onions. Toss continuously for 1–2 minutes until evenly coated.
Serve hot, topped with sesame seeds, chilli oil, and a drizzle of black vinegar if desired.