Preheat your oven to 400°F and line a large sheet pan with parchment paper for easy cleanup.
Peel and cube the sweet potato into 1-inch pieces, then toss them on the pan with half of the olive oil, sea salt, and black pepper.
Roast the sweet potatoes for 12 minutes to give them a head start on caramelizing.
While the potatoes roast, whisk together the remaining olive oil, lemon juice, lemon zest, minced garlic, rosemary, and thyme in a small bowl.
Remove the pan from the oven, move the potatoes to one side, and place the chicken breast and broccoli florets on the other side.
Brush the lemon-herb mixture generously over the chicken and drizzle any remaining over the broccoli and potatoes.
Return the pan to the oven and roast for another 18-20 minutes, or until the chicken reaches an internal temperature of 165°F.
Let the chicken rest for 5 minutes before slicing to keep it juicy.