In a large skillet, heat olive oil over medium heat. Add chicken and season with salt, pepper, and garlic powder. Cook until no longer pink, about 4-5 minutes per side. To achieve the golden color, try not to move chicken until ready to flip. Remove to a separate plate and set aside.
Wipe skillet, if needed, and add more olive oil. Add broccoli and mushrooms and sauté until broccoli is crisp-tender, about 5-6 minutes.
As vegetables cook, in a medium bowl, whisk chicken broth, soy sauce, rice vinegar, honey, sesame oil, garlic and ginger. **If you like extra sauce, feel free to double ingredients**
Once vegetables are tender, add chicken back to skillet and pour in sauce. Stir to combine.
In a small bowl, stir cornstarch and cold water until dissolved. Stir into pan. Cook for 2-3 minutes, or until sauce is thickened. Serve over rice or noodles, if desired.