Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Cut the chicken breast into 1-inch bite-sized cubes and place them in a large mixing bowl.
In a small bowl, whisk together the orange juice, tamari, honey, sesame oil, grated ginger, minced garlic, arrowroot powder, sea salt, and black pepper until the starch is fully dissolved.
Pour half of the prepared orange glaze over the chicken cubes and toss until every piece is thoroughly coated.
Spread the glazed chicken and the broccoli florets in a single layer on the prepared baking sheet, ensuring they are not overcrowded.
Bake for 15-18 minutes, or until the chicken is cooked through and the broccoli edges are slightly charred and tender-crisp.
Remove from the oven and immediately drizzle the remaining half of the orange glaze over the hot chicken and broccoli.
Serve the orange chicken and broccoli over the warm cooked brown rice while the glaze is glossy and fresh.