Cut the chicken into 1/2 inch pieces.
Add the cornstarch and chicken to a large zip up bag. Zip it closed and shake to coat the chicken in cornstarch.
Make the sauce by combining chicken broth, soy sauce, brown sugar, sesame oil, rice vinegar and garlic. Whisk together.
Heat the oil in a large frying pan or wok. Add the chicken, salt and pepper. Cook until the chicken is no longer pink.
While the chicken is cooking put the cashews in a zip up bag. Use a meat mallet to break the cashews into smaller pieces.
Add the sauce and cashews to the chicken. Simmer for 5 minutes, until the sauce thickens.