Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper for easy cleanup.
Dice the sweet potato into small half-inch cubes and place them on one side of the baking sheet.
Place the chicken breast on the other side of the pan and drizzle both the chicken and potatoes with half of the olive oil.
Season the chicken and potatoes with a pinch of sea salt and black pepper, then roast in the oven for 10 minutes.
While the chicken is roasting, toss the broccoli florets and sliced bell peppers in a bowl with the remaining olive oil, minced garlic, lemon juice, and dried oregano.
Remove the pan from the oven, add the seasoned broccoli and peppers to the sheet, and return to the oven for an additional 15 to 18 minutes.
Ensure the chicken has reached an internal temperature of 165°F and the vegetables are tender and slightly caramelized.
Let the chicken rest for 5 minutes before slicing to ensure it stays juicy, then serve alongside the roasted vegetable medley.