Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper for easy cleanup.
Scrub the sweet potato and dice into 1/2-inch cubes, then slice the carrots into thin rounds and chop the bell pepper into bite-sized pieces.
Place the chicken breast on one side of the prepared baking sheet and arrange the sweet potatoes, broccoli, carrots, and peppers on the other side.
Drizzle the olive oil over the chicken and the vegetable medley, ensuring everything is lightly coated.
Sprinkle the dried oregano, garlic powder, sea salt, and black pepper evenly over both the chicken and the vegetables.
Toss the vegetables with tongs to distribute the seasoning and rub the spices into both sides of the chicken breast.
Roast in the center of the oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the sweet potatoes are fork-tender.
Allow the chicken to rest for 5 minutes before slicing against the grain to maintain its moisture.
Garnish the entire plate with freshly chopped parsley and serve immediately while hot.