Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper.
Dice the sweet potato into 1/2-inch cubes, chop the red bell pepper into bite-sized pieces, and cut the chicken breast into even 1-inch strips.
In a small bowl, whisk together the extra virgin olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper to create the marinade.
Place the chicken, sweet potato cubes, broccoli florets, and bell peppers onto the prepared sheet pan.
Drizzle the lemon-herb marinade over the chicken and vegetables, tossing thoroughly with your hands or tongs to ensure every piece is evenly coated.
Spread the ingredients out into a single layer, ensuring they aren't overcrowded so they roast rather than steam.
Roast in the center of 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 serve immediately while the vegetables are crisp-tender and the chicken is juicy.