Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper.
Dice the sweet potato into 1/2-inch cubes and mince the fresh garlic cloves.
In a small bowl, whisk together the olive oil, dried oregano, garlic powder, sea salt, black pepper, and minced garlic.
Place the chicken breast, sweet potato cubes, and broccoli florets on the prepared sheet pan.
Drizzle the herb oil mixture over the chicken and vegetables, tossing the produce to coat evenly and rubbing the mixture into the chicken.
Slice half of the lemon into thin rounds and place them on top of the chicken; reserve the other half for later.
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.
Remove from the oven and squeeze the remaining lemon juice over the entire pan before serving.