Cut the chicken breasts into 1-inch pieces and season with salt and pepper to taste. Place in a ziplock bag with cornstarch and shake to coat.
Heat vegetable oil in a wok over medium-high heat. Once hot, add the coated chicken and cook until golden brown, about 5 to 7 minutes, stirring occasionally.
In a bowl, whisk together soy sauce, chicken broth, minced garlic, brown sugar, Hoisin sauce, and sesame oil. Pour over the cooked chicken.
Add cashews to the pan and toss everything together until well combined and the sauce has thickened. Serve over rice or vegetables if desired.
