Place the chicken in a bowl with 1/4 cup cornstarch and salt and pepper. Toss to coat chicken evenly.
In a large non stick pan, or wok, heat the oil over medium-high heat. Sauté the chicken, stirring often, until golden brown and cooked through, about 5 to 8 minutes. Transfer the cooked chicken to a plate .
leaving 1 teaspoon of oil in the pan. Add the garlic and ginger and cook for 30 seconds.
In a bowl, whisk together the chicken broth, soy sauce, rice vinegar, and brown sugar. Pour the sauce mixture into the pan.
Bring the sauce to a simmer. Place the cornstarch in a bowl with 2 tablespoons cold water and whisk to combine.
Pour the cornstarch into the pan and bring to a boil. Cook for 1 minute or until sauce has just thickened.
Place the chicken and cashews in the pan and toss to coat with the sauce. Sprinkle with green onions and serve.
Serve over cooked white rice.