In a small bowl, whisk 1 Tbsp. water with cornstarch until smooth. Whisk in honey, soy sauce and broth.
Warm oil in a large skillet over high heat. Add onion, garlic, ginger and crushed red pepper; cook for 30 seconds, stirring constantly.
Add chicken and stir-fry until opaque, 5 to 6 minutes. Add snow peas, bell pepper and cashews and continue stir-frying for 1 to 2 minutes. Stir reserved sauce and pour it into skillet. Cook for 1 to 2 minutes longer, stirring constantly, until sauce is bubbling and has thickened. Drizzle with sesame oil and serve over rice, if desired.