Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper for easy cleanup.
Dice the chicken breast into uniform 1-inch cubes and season them evenly with the sea salt and black pepper.
In a small mixing bowl, whisk together the orange juice, coconut aminos, rice vinegar, honey, sesame oil, arrowroot powder, minced ginger, and minced garlic until smooth.
Spread the chicken cubes and broccoli florets across the prepared baking sheet in a single layer.
Pour the orange sauce over the chicken and broccoli, tossing thoroughly with tongs to ensure every piece is well coated.
Bake for 15 to 18 minutes, tossing halfway through, until the chicken is cooked through and the sauce has thickened into a sticky glaze.
Divide the cooked brown rice into bowls, top with the orange chicken and broccoli, and finish with a sprinkle of sesame seeds.