Cut the chicken breast into bite-sized pieces and toss in a bowl with arrowroot powder until evenly coated.
In a small glass jar or bowl, whisk together the coconut aminos, rice vinegar, honey, minced ginger, minced garlic, and red pepper flakes.
Steam the broccoli florets in a steamer basket over boiling water for 4-5 minutes until tender-crisp and bright green.
Heat the avocado oil in a large non-stick skillet over medium-high heat.
Add the chicken to the hot skillet in a single layer and sear until golden brown and cooked through, approximately 3-4 minutes per side.
Pour the prepared sauce mixture into the skillet with the chicken, stirring constantly for 1-2 minutes until the sauce thickens into a glossy glaze.
Place the cooked brown rice in a bowl and top with the glazed chicken and steamed broccoli.
Garnish the dish with sesame seeds and thinly sliced green onions before serving.