Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Scrub the sweet potato and cut it into uniform 1-inch cubes to ensure even roasting.
Place the chicken breast and sweet potato cubes on the prepared baking sheet.
In a small bowl, whisk together the olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper.
Drizzle the herb mixture over the chicken and sweet potatoes, tossing the potatoes with your hands or a spatula to coat them thoroughly.
Roast in the oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the sweet potatoes are fork-tender and slightly browned.
While the chicken is roasting, steam the broccoli florets in a steamer basket over boiling water for about 5 minutes until they are bright green and tender-crisp.
Allow the chicken to rest for 5 minutes before slicing it into strips.
Plate the sliced chicken alongside the roasted sweet potatoes and steamed broccoli, drizzling any remaining juices from the pan over the top.