Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Peel the sweet potatoes and cut them into 1/2-inch cubes, then chop the red bell pepper into bite-sized pieces.
Place the chicken breasts, cubed sweet potatoes, broccoli florets, and bell peppers onto the prepared sheet pan.
In a small mixing bowl, whisk together the extra virgin olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper.
Drizzle the lemon-herb dressing over the chicken and vegetables, tossing everything thoroughly with your hands or tongs to ensure an even coating.
Spread the ingredients out into a single layer, making sure the chicken pieces are not crowded by the vegetables to ensure they roast properly.
Slide the pan into the oven and roast for 20 to 25 minutes, or until the chicken is cooked through to an internal temperature of 165°F and the sweet potatoes are fork-tender.
Remove from the oven and let the chicken rest for 5 minutes before slicing to keep it juicy, then serve immediately.