Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Cut the chicken breast into 1-inch cubes and place them in a bowl, tossing with olive oil, sea salt, and black pepper until evenly coated.
Spread the chicken cubes in a single layer on the prepared baking sheet and bake for 15-18 minutes until cooked through and slightly golden.
While the chicken is baking, combine the orange juice, orange zest, tamari, honey, minced ginger, minced garlic, and arrowroot starch in a small saucepan.
Whisk the sauce over medium-low heat for 3-5 minutes until it thickens into a glossy, translucent glaze.
Steam the broccoli florets in a steamer basket over boiling water for about 5 minutes until tender-crisp and bright green.
Remove the chicken from the oven and transfer it to a clean bowl, pouring the warm orange glaze over the top and tossing to coat every piece.
Serve the glazed chicken immediately over the cooked brown rice with steamed broccoli on the side, garnished with sesame seeds.