Preheat the oven to 375°F (190°C) and lightly spray or oil an oven-safe baking dish.
In a small bowl, whisk together soy sauce, chicken stock, hoisin sauce, rice vinegar, sesame oil, brown sugar or honey, grated ginger, minced garlic, cornstarch, crushed red pepper, cracked pepper, and sriracha (if using) until smooth.
Place the cut chicken, broccoli florets, diced red bell pepper, chopped green onions, and cashews in a large mixing bowl (or directly in the prepared baking dish).
Pour the sauce over the chicken and vegetables and toss gently to coat everything evenly; season with salt to taste.
Transfer the mixture to the baking dish if you mixed in a bowl, spreading into an even layer.
Bake for 20–24 minutes, or until the chicken reaches an internal temperature of 165°F (74°C) and the vegetables are tender-crisp.
Remove from the oven and let sit for a few minutes so the sauce thickens slightly, then serve over rice or as desired.