CHICKEN: In a small bowl, combine the chicken with 2 teaspoons of cornstarch, 1 tablespoon of cold water, minced garlic, 1 teaspoon sesame oil, 2 teaspoons golden mountain sauce, and set aside to marinate while you prepare the sauce. See notes for make-ahead option.
SAUCE: In a small bowl, stir together 3 tablespoons cold water, soy sauce, and 1 teaspoon cornstarch. When combined, add the fish sauce, oyster sauce, sugar, 2 teaspoons toasted sesame oil and 2 teaspoons golden mountain sauce; set aside for later.
COOK: Add the last teaspoon of toasted sesame oil in a large skillet over medium heat. Then, add the cashews and roast the nuts for roughly 1-2 minutes or until toasted; remove to a bowl, and set aside for later. Kick the heat up to medium-high, add the 2 tablespoons of oil, when heated through, add the marinated chicken and sprinkle with red pepper flakes. Cook the chicken for 1-2 minutes or until about halfway done. Then, add the mushrooms, carrots, white onions and continue to cook until the chicken is no longer pink and the veggies are cooked. Drizzle with the prepared sauce, stir to combine. When the sauce has thickened, add the scallions and the cashews to the skillet. Serve warm over jasmine rice.