Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Prepare the vegetables by halving the Brussels sprouts, slicing the carrots into rounds, and cubing the sweet potato into 1/2-inch pieces.
Mince the garlic clove and place it in a large mixing bowl with the olive oil, rosemary, thyme, sea salt, and black pepper.
Pat the chicken breast dry and slice it into even 1-inch strips or bite-sized pieces.
Add the chicken and all the vegetables to the bowl with the oil and herb mixture, tossing thoroughly until everything is evenly coated.
Spread the mixture in a single layer on the prepared baking sheet, ensuring the pieces are not overcrowded to allow for proper browning.
Roast in the oven for 20 to 25 minutes, or until the chicken is cooked through and the vegetables are tender and golden-brown.
Remove from the oven and let the chicken rest for 2 minutes before serving to ensure it stays juicy.