Slice chicken into bite-sized pieces.
Roll chicken pieces in cornstarch. Marinate in soy sauce, sesame oil, and sugar.
While chicken is marinating, chop veggies and prep rice. Mix sauce in a small bowl or measuring cup. Set aside.
Stir fry chicken in small batches in wok or large skillet. Drain in colander or on paper towels.
Stir fry or steam veggies.
Return chicken to pan and pour in sauce. It should thicken quickly. Add veggies to saucy pan if desired. Sprinkle cashews over top. Garnish with cilantro if desired.
Serve over jasmine rice.