In a mixing bowl, combine the thinly sliced chicken breast, egg white, 1 tablespoon of cornstarch, and 1 tablespoon of soy sauce. Mix well and marinate for about 15 minutes.
Slice the onion and bell pepper, and chop your mixed vegetables into bite-sized pieces. Set them aside.
In a wok or large skillet, heat 2 tablespoons of vegetable oil over medium-high heat until hot.
Add the marinated chicken to the hot oil, spreading it out in a single layer. Cook for about 3-4 minutes without stirring, then stir until fully cooked.
In the same pan, add the minced garlic and sliced onion. Stir-fry for about 1-2 minutes until the onion becomes translucent.
Add the sliced bell pepper and mixed vegetables to the pan. Stir-fry for about 3-5 minutes, or until tender but still crisp.
In a bowl, mix together 1/2 cup of soy sauce, 2 tablespoons of oyster sauce, 1 teaspoon of sugar, and 1 cup of chicken broth. Pour over the sautéed vegetables and bring to a simmer.
Stir the cornstarch and water mixture into the sauce and continue stirring until thickened.
Add the cooked chicken back into the pan and stir well to coat everything with the sauce. Season with salt and pepper to taste.
Serve your Chop Suey Stir Fry hot over a bed of steamed rice or noodles.
