Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper.
Peel and dice the sweet potato into 1-inch cubes, then place them on one side of the sheet pan.
Drizzle the sweet potatoes with 0.5 tbsp of olive oil and a pinch of salt and pepper, tossing to coat evenly.
Place the sweet potatoes in the oven to roast for 10 minutes while you prepare the chicken.
In a small bowl, whisk together the remaining 0.5 tbsp olive oil, lemon juice, lemon zest, oregano, garlic powder, and the remaining salt and pepper.
Pat the chicken breast dry with a paper towel and rub the lemon-herb mixture over all sides of the meat.
Remove the sheet pan from the oven, push the potatoes to one side, and add the chicken breast and broccoli florets to the empty space.
Lightly mist the broccoli with a small amount of oil spray if desired, or toss with any remaining herb mixture.
Return the pan to the oven and roast for an additional 15-20 minutes, or until the chicken reaches an internal temperature of 165°F.
Let the chicken rest for 5 minutes before slicing to ensure it stays juicy and tender.