Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper.
Cut the chicken breast into bite-sized 1-inch cubes and place them in a large mixing bowl.
Chop the broccoli into small florets, the bell pepper and red onion into 1-inch pieces, and the sweet potato into small 0.5-inch cubes.
Add all the vegetables to the bowl with the chicken.
Drizzle the extra virgin olive oil over the chicken and vegetables.
Sprinkle the sea salt, black pepper, garlic powder, and dried oregano over the mixture.
Toss everything thoroughly until the chicken and vegetables are evenly coated in oil and spices.
Spread the mixture in a single layer on the prepared sheet pan, ensuring nothing is overcrowded to allow for proper roasting.
Roast in the oven for 20-25 minutes, or until the chicken is cooked through and the sweet potatoes are fork-tender.
Remove from the oven and drizzle with fresh lemon juice before serving.