Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Cut the chicken breast into one-inch cubes and place them in a bowl with the broccoli florets.
Toss the chicken and broccoli with avocado oil, sea salt, and black pepper until evenly coated.
Spread the mixture in a single layer on the prepared baking sheet and roast for 15 to 18 minutes until the chicken is cooked through.
While the chicken roasts, whisk together the orange juice, coconut aminos, rice vinegar, honey, arrowroot powder, ginger, and garlic in a small saucepan.
Place the saucepan over medium heat and whisk constantly until the sauce simmers and thickens into a glossy glaze.
Remove the baking sheet from the oven, pour the thickened orange glaze over the chicken and broccoli, and toss to combine.
Serve the glazed orange chicken and broccoli over the warm cooked brown rice.