Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
Peel and dice the sweet potato into 1/2-inch cubes.
In a small bowl, whisk together the olive oil, lemon juice, lemon zest, dried oregano, garlic powder, sea salt, and black pepper.
Place the chicken breast and diced sweet potatoes on the prepared baking sheet.
Brush the chicken and toss the sweet potatoes with the lemon-herb oil mixture until evenly coated.
Roast in the oven for 20-25 minutes, or until the chicken reaches an internal temperature of 165°F and the potatoes are tender.
While the chicken roasts, steam the broccoli florets for 4-5 minutes until bright green and tender-crisp.
Let the chicken rest for 5 minutes before slicing, then serve alongside the roasted sweet potatoes and steamed broccoli.