In a small bowl, whisk together the tamari, honey, minced garlic, grated ginger, and water to create the sauce.
Pat the chicken breast dry and dice into bite-sized pieces, then season 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 sear for 5-6 minutes, turning occasionally, until golden brown and cooked through.
Remove the chicken from the pan and set aside; add the broccoli and sliced bell peppers to the same pan with an extra splash of water.
Cover the pan for 2 minutes to steam the vegetables until they are bright green and tender-crisp.
Return the chicken to the pan and pour the honey-garlic sauce over the mixture.
Toss everything together for 1-2 minutes until the sauce thickens into a glossy glaze that coats the chicken and vegetables.
Serve the stir-fry immediately over a bed of warm brown rice and garnish with sesame seeds.