Cut chicken breast into 1-inch bite-sized pieces.
In a small bowl, whisk together coconut aminos, rice vinegar, honey, arrowroot powder, grated ginger, minced garlic, and red pepper flakes.
Heat avocado oil in a large skillet or wok over medium-high heat.
Add chicken pieces to the skillet and sear until golden brown and cooked through, about 5-7 minutes.
Add broccoli and a splash of water to the pan, covering for 2 minutes to steam until tender-crisp.
Pour the sauce mixture over the chicken and broccoli, tossing constantly until the sauce thickens into a glossy glaze.
Serve the chicken and broccoli over the warm cooked brown rice.
Garnish with sesame seeds and sliced green onions.