Preheat oven to 400°F and line a large sheet pan with parchment paper.
Peel the carrots and slice them into 1-inch diagonal coins, then cut the red onion into 1-inch wedges.
Cut the chicken breast into even 1.5-inch bite-sized pieces to ensure uniform cooking.
In a small bowl, whisk together the olive oil, maple syrup, coconut aminos, Dijon mustard, sea salt, black pepper, and garlic powder.
Place the chicken, carrots, and onions on the prepared sheet pan and pour the glaze over them, tossing well to coat every piece.
Spread the ingredients into a single layer, ensuring they are not crowded so they roast rather than steam.
Bake for 20-25 minutes, tossing halfway through, until the chicken is cooked through and the carrots are fork-tender with golden edges.