Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Cut the chicken breast into 1-inch bite-sized cubes and season evenly with sea salt and black pepper.
In a small mixing bowl, whisk together the orange juice, coconut aminos, rice vinegar, honey, garlic powder, ground ginger, and arrowroot powder until smooth.
Place the chicken cubes and broccoli florets on the prepared baking sheet, drizzle with sesame oil, and toss to coat.
Pour half of the orange sauce mixture over the chicken and broccoli, tossing again to ensure everything is well-glazed.
Spread the ingredients into a single layer and bake for 15 to 18 minutes, or until the chicken is cooked through and the broccoli is tender-crisp.
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 syrup.
Remove the tray from the oven, drizzle the thickened sauce over the chicken and broccoli, and serve immediately over the warm cooked brown rice.