Preheat your oven to 400°F 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 bowl with the avocado oil, sea salt, and black pepper, tossing to coat evenly.
Spread the chicken cubes and the broccoli florets in a single layer on the prepared baking sheet.
Roast for 15 to 18 minutes, or until the chicken is cooked through and the broccoli is tender-crisp.
While the chicken roasts, combine the orange juice, orange zest, coconut aminos, rice vinegar, minced garlic, grated ginger, and arrowroot powder in a small saucepan.
Whisk the sauce over medium heat for 3 to 5 minutes until it simmers and thickens into a glossy, translucent glaze.
Remove the baking sheet from the oven and transfer the chicken and broccoli to a large bowl.
Pour the thickened orange glaze over the chicken and broccoli, tossing gently to ensure every piece is well-coated.
Serve immediately over the warm, cooked brown rice.