Whisk the orange juice, tamari, honey, minced ginger, garlic, and arrowroot powder in a small bowl until the arrowroot is fully dissolved.
Season the diced chicken breast evenly with sea salt and black pepper.
Heat the avocado oil in a large skillet or wok over medium-high heat until shimmering.
Add the chicken to the skillet and cook until golden brown and cooked through, approximately 5 to 6 minutes.
Remove the chicken from the skillet and set aside, then add the broccoli florets and sliced bell peppers to the same pan.
Stir-fry the vegetables for 3 to 4 minutes until they are tender-crisp and bright in color.
Return the chicken to the skillet and pour the orange glaze over the chicken and vegetables.
Stir constantly for 1 to 2 minutes until the sauce thickens into a glossy glaze that coats every piece.
Serve the stir-fry immediately over warm brown rice and garnish with a sprinkle of sesame seeds.