In a medium bowl, toss the sliced chicken with 1 tablespoon of soy sauce, garlic powder, and onion powder. Mix well, then add 2 tablespoons of cornstarch and ensure the chicken is well-coated. Set aside.

In a small bowl, whisk together the chicken stock, brown sugar, 3 tablespoons of soy sauce, oyster sauce, rice wine vinegar, and 2 teaspoons of cornstarch. Set this mixture aside for later.

Heat 1 tablespoon of vegetable oil in a wok or large skillet over medium-high heat. Once hot, add the marinated chicken in a single layer. Allow it to sauté for about 30 seconds before tossing. Cook until browned and cooked through, roughly 5-6 minutes. Remove the chicken and set aside on a plate.

Add another tablespoon of oil and toss in the mushrooms. Stir them until they soften, about 2 minutes. Remove and place them on the plate with the chicken.

In the same pan, add the remaining tablespoon of oil and sauté the zucchini until they are tender-crisp, about 2-3 minutes. Transfer them to the same plate.

Add minced ginger and garlic into the skillet, cooking until fragrant for about 30 seconds. Pour in the prepared sauce and let it bubble before returning the chicken, mushrooms, and zucchini to the pan. Stir everything to coat in the sauce and let it simmer for an additional 1-2 minutes until warmed through and thickened.

Garnish with sesame seeds and sliced scallions, if desired. Serve immediately and enjoy!