Bring a medium pot of salted water to a boil over high heat. Add the green beans and cook 2 minutes, until tender crisp. Drain and run under cold water to cool down then drain again.
In a small bowl, combine the soy sauce, broth, vinegar, cornstarch, and sriracha and stir until the cornstarch is dissolved.
In a wok or large skillet, heat the oil over high heat. Add the ginger and garlic and cook stirring constantly for 10 seconds. Add the chicken and cook stirring constantly, until no trace of pink remains on the surface. Add green beans and the soy sauce mixture and cook, stirring constantly, until the chicken is cooked thoroughly, about 2 minutes. Stir in the cashews and serve.