How to Make It
Preheat oven to 400ºF. Line a rimmed baking sheet with foil and lightly grease with oil.
Whisk together hoisin, tamari, vinegar, and 2 tablespoons oil in a small bowl. Set aside ¼ cup of the mixture for serving.
Toss broccoli with garlic, salt, remaining 2 tablespoons oil, and chile, if desired, in a large bowl; set aside.
Place chicken on prepared sheet. Brush all over with half of the hoisin mixture. Bake 20 minutes, then add broccoli mixture to pan.
Continue baking until broccoli is golden and chicken is cooked through, about 20 minutes more.
Serve with reserved sauce and rice.