Cut the chicken into small bite-size pieces and toss with the baking soda in a small bowl; refrigerate covered for 15 minutes to tenderize.
After 15 minutes, rinse the chicken thoroughly in a fine mesh sieve and pat dry with paper towels; set aside.
Prepare the vegetables: finely shred the cabbage, mince the ginger and garlic, julienne the carrots, thinly slice the celery, and thinly slice the green onions separating about 1/4 cup whites from the green tops.
In a small bowl whisk the cornstarch and soy sauce until smooth, then stir in the oyster sauce, chicken stock, brown sugar, sesame oil, and pepper; reserve the sauce.
Cook the chow mein noodles according to package directions, rinse under cold water, drain, and set aside.
Heat the vegetable oil in a large pan over high heat. Add the white parts of the green onions and cook 1–2 minutes, then add the garlic and ginger and cook about 20 seconds, taking care not to burn them.
Add the chicken and stir constantly for about 1 minute until lightly browned on the outside.
Add the shredded cabbage, julienned carrots, and sliced celery; stir continuously for 1–2 minutes until vegetables are crisp-tender and cabbage is wilted.
Toss in the cooked noodles and pour the reserved sauce over everything; toss with tongs for about 1 minute until the sauce thickens and coats the noodles.
Stir in the reserved green parts of the green onions, adjust seasoning if desired, and serve immediately.