Whisk orange juice, tamari, ginger, garlic, and arrowroot powder in a small bowl until the starch is fully dissolved.
Season the chicken pieces evenly with sea salt and black pepper.
Heat the sesame oil in a large non-stick skillet over medium-high heat until shimmering.
Add chicken to the skillet, searing for 5-7 minutes until golden brown and the internal temperature reaches 165 degrees Fahrenheit.
Remove the chicken from the skillet and set aside on a plate.
Toss the broccoli florets and sliced bell peppers into the hot skillet, sautéing for 4 minutes until they reach a vibrant green and crisp-tender texture.
Pour the orange sauce mixture into the skillet with the vegetables, stirring constantly as it begins to bubble and thicken.
Return the cooked chicken to the skillet, tossing everything together until the pieces are thoroughly coated in the glossy glaze.
Serve the stir-fry immediately over the warm cooked brown rice for a complete, balanced meal.