Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Peel and dice the sweet potato into 1/2-inch cubes, and finely mince the garlic, rosemary, and thyme.
In a medium bowl, toss the chicken breast, diced sweet potatoes, and minced garlic with the olive oil, rosemary, thyme, salt, and pepper until evenly coated.
Spread the chicken and sweet potatoes onto the prepared baking sheet in a single layer, ensuring they are not overcrowded.
Roast in the oven for 15 minutes, then remove the pan and add the broccoli florets, tossing them quickly in the pan juices.
Return the pan to the oven and roast for another 10-12 minutes until the chicken reaches an internal temperature of 165°F and the potatoes are tender.
Drizzle the entire dish with fresh lemon juice before serving hot.