• Preheat the oven to 350°F and place the cashews on a rimmed baking sheet. Bake for 7-8 minutes or until fragrant. Remove from the oven and allow to cool.

For the Chicken

• In a large bowl mix together 2 tablespoons of cornstarch, salt, and pepper. Pat chicken dry with a paper towel. Cut the chicken breast into 1-inch cubes. Place chicken cubes into the cornstarch-spice bowl and toss until well coated.
• Heat 2 tablespoons of oil in a large nonstick skillet over medium-high heat. Add the chicken to the skillet in an even layer. Cook for about 8-10 minutes, turning every 2-3 minutes to allow the chicken to become golden brown and crispy. Cover the pan, reduce the heat to medium-low, and cook for an additional 3-5 minutes to fully cook the chicken. Use a meat thermometer to check the chicken to ensure it reaches 165°F. Remove the chicken from the pan with a slotted spoon, leaving behind any oil in the pan, and place into a bowl and set aside.

Add the Sauce

• Add the remaining 1 tbsp vegetable oil with onion and bell pepper and cook over medium-high heat for 8-10 minutes, mixing often. Once the veggies are somewhat cooked, add the garlic, ginger, and white parts of the scallion, and saute for 1-2 minutes until fragrant. 
• Whisk in brown sugar, soy sauce, hoisin sauce, rice vinegar, 1⁄4 cup water and add the cooked chicken, and bring the liquid to a simmer.
• In a small bowl, whisk together the remaining cornstarch with water. Mix this cornstarch slurry into the pan. Mix everything together until the sauce thickens.
• Turn off the heat and mix in the cashews. Taste and add more salt if needed.
• Serve over white rice, and garnish with the green parts of the scallion.