Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Peel and dice the sweet potato into 1/2-inch cubes and slice the carrots into rounds.
Mince the garlic cloves and finely chop the fresh rosemary and thyme.
In a large bowl, whisk together the olive oil, minced garlic, rosemary, thyme, sea salt, and black pepper.
Place the chicken breast, sweet potato cubes, carrots, and broccoli florets into the bowl and toss thoroughly until everything is evenly coated in the herb oil.
Spread the chicken and vegetables in a single layer on the prepared sheet pan, ensuring they aren't overcrowded so they roast rather than steam.
Roast in the oven for 20-25 minutes, or until the chicken reaches an internal temperature of 165°F and the sweet potatoes are tender and golden.
Remove from the oven and drizzle the fresh lemon juice over the chicken and vegetables before serving.