Preheat oven to 400°F and line a baking sheet with parchment paper.
In a small bowl, whisk together orange juice, orange zest, soy sauce, honey, minced garlic, grated ginger, and cornstarch.
Cut the chicken breast into bite-sized pieces and toss with the broccoli florets in a large bowl.
Season the chicken and broccoli with sea salt, black pepper, and half of the prepared orange sauce.
Spread the mixture in a single layer on the baking sheet and bake for 15-18 minutes until the chicken is cooked through.
While the chicken bakes, pour the remaining sauce into a small saucepan and simmer over medium heat until it thickens into a glaze.
Drizzle the thickened glaze over the baked chicken and broccoli and toss to coat.
Serve the orange chicken and broccoli over the cooked brown rice and garnish with sesame seeds and sliced green onions.