Whisk the coconut aminos, rice vinegar, honey, and arrowroot powder in a small bowl to create the sweet and sour sauce.
Season the diced chicken breast evenly with the sea salt and black pepper.
Heat the toasted sesame oil in a large skillet or wok over medium-high heat until shimmering.
Add the chicken to the skillet and sauté until golden brown and cooked through, approximately 5-6 minutes.
Remove the chicken from the pan and set it aside on a plate.
In the same pan, add the red and green bell peppers along with the broccoli florets, stir-frying for 3-4 minutes until tender-crisp.
Stir in the minced garlic, grated fresh ginger, and pineapple chunks, cooking for an additional minute until fragrant.
Return the cooked chicken to the skillet and pour the prepared sauce over the mixture.
Toss everything together for 1-2 minutes until the sauce thickens into a glossy glaze that coats the ingredients.
Serve the stir-fry immediately over the warm cooked brown rice.