In a small bowl, whisk together tamari, rice vinegar, honey, minced garlic, grated ginger, and red pepper flakes.
Pat the chicken breast pieces dry with a paper towel, then season with sea salt and black pepper.
Toss the chicken in a bowl with arrowroot powder until each piece is lightly and evenly coated.
Heat avocado oil in a large skillet over medium-high heat and sear the chicken until golden brown and cooked through.
While chicken cooks, steam the broccoli in a steamer basket for 4-5 minutes until tender-crisp.
Pour the prepared sauce into the skillet with the chicken, stirring constantly for 1-2 minutes until the glaze is thick and glossy.
Divide the cooked brown rice and steamed broccoli into bowls, topping with the glazed chicken.
Garnish with sesame seeds and sliced green onions before serving.