Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Pat the chicken breast dry with a paper towel and cut it into 1-inch bite-sized cubes.
Peel and dice the sweet potato into 1/2-inch cubes, chop the broccoli into bite-sized florets, slice the bell pepper into strips, and cut the red onion into wedges.
Place the chicken cubes and all the prepared vegetables onto the sheet pan in a single layer.
Drizzle the extra virgin olive oil over the chicken and vegetables, then sprinkle evenly with sea salt, black pepper, garlic powder, and dried oregano.
Use your hands or tongs to toss everything together until every piece is thoroughly and evenly coated with oil and seasoning.
Spread the mixture out across the pan, ensuring nothing is overcrowded so the vegetables can roast rather than steam.
Roast in the oven for 20 to 25 minutes, tossing the medley halfway through, until the chicken is cooked through and the vegetables are caramelized and tender.
Remove from the oven and let the dish rest for 2 minutes before serving warm.