Heat sesame oil in a wok or deep skillet over medium-high heat.

Add chicken cubes and stir-fry until partially cooked and lightly browned.

Add broccoli flowerets, sliced mushrooms, water chestnuts, and diced onion to the wok.

Stir-fry the vegetables and chicken until the broccoli is tender-crisp.

Pour in chicken broth, soy sauce, and cornstarch slurry (cornstarch blended with cool water).

Continue to cook and stir until the sauce thickens and coats the chicken and vegetables.

Serve hot over white rice.