In a bowl, combine the sliced chicken breast with 1 tablespoon of soy sauce and 1 tablespoon of cornstarch. Mix well to coat the chicken evenly. This step helps to tenderize the chicken and create a nice texture when cooked.

In a small bowl, whisk together 2 tablespoons of soy sauce, 1 tablespoon of oyster sauce, 1 tablespoon of rice vinegar, 1 tablespoon of sesame oil, 1 tablespoon of water, and 1 teaspoon of sugar until well combined. Set aside.

Heat a wok over medium-high heat and add 1 tablespoon of vegetable oil. Once the oil is hot, add the marinated chicken strips. Stir fry for about 3-4 minutes until the chicken is cooked through and lightly browned. Remove the chicken from the wok and set aside.

In the same wok, add a little more oil if needed, then add the minced garlic and grated ginger. Stir fry for about 30 seconds until fragrant. Add the shredded cabbage, julienned carrots, and sliced bell pepper. Stir fry for 3-5 minutes until the vegetables are tender-crisp.

Return the cooked chicken to the wok with the vegetables. Pour the prepared sauce over the mixture and stir well to combine. Cook for an additional 1-2 minutes until everything is heated through and the sauce has thickened slightly. Serve hot, garnished with chopped green onions.