Add 1 lb of chicken thighs to a bowl. Drizzle the sesame oil and shaoxing wine over the chicken.
Mix all the ingredients from flour through chicken stock powder together. Coat the chicken in the flour mixture.
Heat oil over medium heat for 5 minutes. Make sure the oil comes 1/2 inch up the sides of the pan. Fry the chicken pieces until they are brown on all sides. See picture above for reference. Once done, empty onto a plate and set aside.
Heat 2 tablespoons of oil over high heat. Add the onion and saute for 1-2 minutes until it becomes shiny.
Add the green bell pepper, red bell pepper, and minced garlic. Saute until soft (3-5 minutes).
Add the oyster sauce and sauté for 1-2 minutes.
Mix the corn starch with the water to make a corn starch slurry. Add the vinegar, sugar, and corn starch slurry to the pan. Cook for another 1-2 minutes until the sauce thickens.
Pour the cooked vegetables over the fried chicken from step 3 and mix until the chicken is coated in the sauce.
Garnish with green onions (optional) and enjoy!