Preheat the oven to 400ºF and line a baking sheet with parchment paper.
Mix together the cornstarch and soy sauce until the cornstarch completely dissolves, and no lumps remain. Add the honey and garlic, mixing to combine.
Cut your chicken into 1-2 inch cubed pieces. You want them to be as close to the same size as possible. Season with pepper.
Chop your onion, broccoli, and bell peppers into desired size.
Add all the prepped veggies to the baking sheet along with the cut-up and seasoned chicken pieces, spreading everything evenly. Stir the sauce again to make sure the cornstarch hasn't settled to the bottom before pouring the sauce over the chicken and veggies.
Place the baking sheet in the oven and bake for 15 minutes, or until the chicken is no longer pink and the veggies are crisp-tender. Stir once during the cooking time to make sure everything is coated in sauce. Bake for another 10-12 minutes.
Serve immediately with your choice of side, we love to serve this with steamed rice!