Cut the chicken breast into 1-inch cubes and place them in a medium mixing bowl.
Sprinkle the chicken with arrowroot powder, sea salt, and black pepper, tossing until each piece is evenly coated for a light, crispy texture.
In a small glass jar or bowl, whisk together the coconut aminos, rice vinegar, honey, minced garlic, and grated ginger to create the sweet and sour sauce.
Heat the toasted sesame oil in a large 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.
Toss in the chopped red bell pepper and sugar snap peas, sautéing for 2-3 minutes until they are tender yet still vibrant and crisp.
Add the fresh pineapple chunks and pour the prepared sauce over the mixture, stirring constantly for 1 minute as the sauce thickens and glazes the chicken.
Serve the stir-fry immediately over the warm cooked brown rice for a complete, balanced meal.