Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Dice the chicken breast into 1-inch bite-sized pieces and peel and chop the sweet potato into 1/2-inch cubes.
In a small mixing bowl, whisk together the extra virgin olive oil, lemon juice, minced garlic, dried oregano, sea salt, and black pepper.
Place the chicken pieces, sweet potato cubes, and broccoli florets onto the prepared sheet pan.
Drizzle the lemon-herb dressing over the chicken and vegetables, tossing thoroughly to ensure every piece is well-coated.
Spread the mixture into a single, even layer to ensure proper roasting and prevent steaming.
Roast in the center of the oven for 20 to 25 minutes, or until the chicken is cooked through and the sweet potatoes are fork-tender.