1. Bring a medium pot of water to a boil. Add the noodles and cook for 2–3 minutes until al dente. Drain and rinse under warm water. Set aside.

2. Heat sesame oil in a wok or large skillet over medium-high heat. Add garlic and onion, and stir-fry for 1 minute until fragrant.

3. Add the chicken slices to the wok. Season lightly with salt and pepper. Stir-fry for 4–5 minutes until the chicken is golden and cooked through. Remove chicken and set aside.

4. In the same wok, add broccoli, bell pepper, and zucchini. Stir-fry for 3–4 minutes until vegetables are crisp-tender.

5. Return the cooked chicken and noodles to the wok. Pour in soy sauce and oyster sauce (if using). Add chili flakes for heat, if desired. Toss everything over high heat for 1–2 minutes until evenly coated.

6. Remove from heat. Garnish with sliced green onions and toasted sesame seeds. Serve immediately.