Preheat your oven to 400°F and line a large sheet pan with parchment paper for easy cleanup.
Cut the chicken breast into 1-inch cubes and chop the broccoli into bite-sized florets.
In a small mixing bowl, whisk together the orange juice, coconut aminos, rice vinegar, honey, arrowroot powder, minced ginger, minced garlic, and red pepper flakes.
Place the chicken and broccoli on the prepared baking sheet and drizzle with the toasted sesame oil, sea salt, and black pepper.
Pour the orange sauce mixture over the chicken and broccoli, tossing thoroughly until every piece is evenly coated.
Spread the ingredients into a single layer and bake for 15 to 18 minutes, or until the chicken is cooked through and the sauce has thickened into a glaze.
Remove from the oven and garnish with sesame seeds and thinly sliced green onions before serving warm.