Preheat oven to 400°F and line a large baking sheet with parchment paper.
Cut the chicken breast into 1-inch bite-sized pieces and chop the broccoli and bell pepper into uniform florets and strips.
In a small bowl, whisk together the orange juice, coconut aminos, rice vinegar, minced ginger, minced garlic, and arrowroot powder until smooth.
Place the chicken and vegetables on the baking sheet, drizzle with sesame oil, and season with sea salt and black pepper.
Pour half of the orange sauce over the chicken and vegetables, tossing to coat every piece evenly.
Bake for 15-18 minutes until the chicken is cooked through and the broccoli is tender-crisp.
While the tray is in the oven, simmer the remaining sauce in a small saucepan over medium heat until it thickens into a glossy glaze.
Remove the tray from the oven, drizzle with the thickened glaze, and sprinkle with red pepper flakes before serving.