Pat chicken dry and cut into bite-sized pieces, then toss in a bowl with arrowroot starch, garlic powder, salt, and pepper until evenly coated.
In a small jar, whisk together coconut aminos, rice vinegar, honey, tomato paste, ginger powder, and sesame oil to create the stir-fry sauce.
Heat avocado oil in a large skillet or wok over medium-high heat until shimmering.
Add the chicken to the pan in a single layer and sear for 3-4 minutes per side until golden brown and cooked through, then remove and set aside.
Add the bell peppers, broccoli, and snap peas to the same pan, sautéing for 5 minutes until tender-crisp and bright.
Return the chicken to the pan and pour the sauce over the mixture, tossing constantly for 1-2 minutes until the glaze thickens and coats everything beautifully.