Pat the chicken breast dry with a paper towel and cut into even 1-inch cubes.
In a medium bowl, toss the chicken cubes with sea salt, black pepper, and arrowroot powder until each piece is lightly and evenly coated.
In a small jar or bowl, whisk together the pineapple juice, coconut aminos, rice vinegar, and tomato paste until smooth to create the stir-fry sauce.
Heat the avocado 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 without moving for 2-3 minutes to develop a golden crust.
Flip the chicken and continue cooking for another 3 minutes until crispy and cooked through, then remove from the pan and set aside.
In the same skillet, add the chopped bell peppers, broccoli florets, minced garlic, and grated ginger, sautéing for 3-4 minutes until the vegetables are tender-crisp.
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 chicken and vegetables perfectly.