Slice the chicken breast into bite-sized pieces and toss in a bowl with arrowroot powder, sea salt, and black pepper until evenly coated.
Heat the avocado oil in a large skillet or wok over medium-high heat until shimmering.
Add the chicken to the skillet and cook for 5-6 minutes, turning occasionally, until the edges are golden and crispy.
Toss in the broccoli florets, sliced red bell pepper, and diced red onion, sautéing for another 4 minutes until the vegetables are tender-crisp.
In a small jar, whisk together the coconut aminos, rice vinegar, pineapple juice, minced garlic, and grated ginger.
Pour the sauce over the chicken and vegetables, stirring constantly for 1-2 minutes as the sauce thickens into a glossy glaze.
Remove from heat and serve immediately while the chicken is hot and the sauce is bubbly.