Slice chicken thigh into 1" pieces into a bowl with soy sauce, sesame oil, salt, white pepper, avocado oil and cornstarch. Mix until combined and marinate for 20.
Slice celery at an angle into 1" pieces, onion into 1" pedals, and mince garlic and ginger and set aside.
In a small bowl, mix oyster sauce, light soy sauce, coarse black pepper, shaoxing wine (or sherry cooking wine), sugar, chicken stock, and cornstarch and set aside.
Over high heat, cook chicken for 2-3 minutes until cooked through and set aside.
Over high heat, fry garlic and ginger for 15 seconds until fragrant. Add celery and onion and cook for 1-2 minutes. Add back chicken and sauce and continue cooking for 1-2 minutes to combine, until sauce has thickened. Serve with freshly steamed rice & enjoy!