Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Prepare the vegetables by slicing the Brussels sprouts in half and cutting the sweet potato into 1-inch thick wedges.
Place the chicken breast, Brussels sprouts, and sweet potato wedges on the prepared sheet pan in a single layer.
Drizzle the olive oil over the chicken and vegetables, ensuring everything is lightly coated.
Sprinkle the dried oregano, dried thyme, garlic powder, sea salt, and black pepper evenly over all components.
Squeeze the juice of the lemon half over the chicken and vegetables, then place the squeezed lemon rind on the pan to infuse more flavor during roasting.
Toss the vegetables gently to distribute the seasonings, then arrange the chicken in the center of the pan.
Roast for 20-25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are golden-brown and tender.
Remove from the oven and let the chicken rest for 5 minutes before slicing to ensure maximum juiciness.