Pat the chicken breast dry with paper towels and toss in a bowl with arrowroot powder, sea salt, and black pepper until lightly and evenly coated.
Heat the avocado oil in a large non-stick skillet or wok over medium-high heat until shimmering.
Add the chicken to the skillet in a single layer and sear for 3-4 minutes per side until golden brown and cooked through, then remove from the pan and set aside.
In the same skillet, add the bell peppers, red onion, and pineapple chunks, sautéing for 3 minutes until the vegetables are tender-crisp and the pineapple is slightly caramelized.
While the vegetables cook, whisk together the coconut aminos, rice vinegar, honey, and sesame oil in a small bowl to create the sauce.
Return the cooked chicken to the skillet, pour the sauce over the mixture, and toss constantly for 1 minute until the glaze thickens and coats every piece beautifully.
Serve the stir-fry immediately over the warm cooked brown rice for a clean and balanced meal.