Preheat oven to 400°F and lightly grease a 9x13 baking dish with olive oil.
Pat chicken thighs dry and season both sides with salt, garlic powder, and black pepper.
Add uncooked jasmine rice, Soyaki sauce, chicken broth, red onion, bell pepper, and mushrooms to the prepared baking dish. Stir to combine.
Nestle the seasoned chicken thighs into the rice mixture. Cover tightly with aluminum foil and bake for 30–35 minutes.
Remove from the oven and give the rice and vegetables a really good stir. Add the halved green beans, cover tightly again, and return to the oven for an additional 15–25 minutes.
The chicken should reach 175°F, the liquid should be fully absorbed, and the rice should be tender.
If your rice isn’t quite tender, give everything another stir, cover tightly, and bake for an additional 10 minutes.
