Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Cut the chicken breast into uniform 1-inch cubes and place them in a large mixing bowl.
Prepare the vegetables by cutting the broccoli into bite-sized florets, chopping the bell pepper into 1-inch pieces, and cubing the sweet potato.
Add all the vegetables to the bowl with the chicken.
Drizzle the extra virgin olive oil and fresh lemon juice over the chicken and vegetables.
Sprinkle the dried oregano, garlic powder, sea salt, and black pepper evenly over the mixture.
Toss everything together with your hands or a large spoon until every piece is well-coated in the oil and seasonings.
Spread the mixture in a single, even layer on the prepared baking sheet, ensuring there is space between pieces so they roast rather than steam.
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.
Remove from the oven and let the dish rest for 2 minutes before serving to allow the juices to redistribute.