Cook the chow mein noodles according to package directions. Drain well and toss with 1 tsp of the sesame oil to prevent sticking.

In a small bowl, whisk together all sauce ingredients: soy sauce, oyster sauce, toasted sesame oil, sugar, and cornstarch. Set aside.

Heat 1 tbsp of vegetable oil in a large wok or skillet over high heat. Add the sliced chicken and cook until golden and cooked through. Remove from the wok.

Add another tbsp of oil to the hot wok. Spread the cooked noodles in an even layer and cook for 4-5 minutes without moving until the bottom is crispy and golden. Flip and crisp the other side for 3-4 minutes. Remove from the wok.

Add the final tbsp of oil. Sauté the garlic and ginger for 30 seconds until fragrant. Add the cabbage, carrots, and celery, stir-frying for 2-3 minutes until crisp-tender.

Return the chicken and crispy noodles to the wok. Pour the sauce over everything, add the bean sprouts, and toss to combine. Cook for 1-2 minutes until the sauce thickens and coats everything evenly.

Serve immediately, garnished with sliced green onions if desired.