Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
In a small bowl, whisk together the fresh orange juice, orange zest, tamari, rice vinegar, honey, arrowroot powder, minced garlic, and grated ginger.
Cut the chicken breast into bite-sized pieces and place them on one side of the baking sheet, then add the broccoli florets to the other side.
Drizzle the sesame oil over the chicken and broccoli, then season both components with the sea salt and black pepper.
Pour half of the prepared orange sauce over the chicken pieces and toss them thoroughly to ensure every piece is well coated.
Bake for 15 to 18 minutes, or until the chicken is cooked through and the broccoli is tender with slightly charred edges.
While the chicken bakes, pour the remaining sauce into a small saucepan and simmer over medium heat for 2 minutes until it thickens into a glossy glaze.
Toss the baked chicken in the thickened glaze and serve immediately over the warm, cooked brown rice.