Preheat your oven to 400°F (200°C) and heat a grill pan or outdoor grill over medium-high heat.
Chop the red bell pepper and zucchini into bite-sized pieces.
On a large baking sheet, toss the broccoli florets, bell pepper, and zucchini with half of the olive oil, sea salt, and black pepper.
Roast the vegetables in the oven for 15-20 minutes until they are tender and slightly charred at the edges.
While the vegetables roast, whisk together the remaining olive oil, lemon juice, garlic powder, and dried oregano in a small bowl.
Brush the chicken breast with the lemon-herb mixture and grill for 6-7 minutes per side, or until the internal temperature reaches 165°F.
Allow the chicken to rest for 3 minutes before slicing and serving alongside the roasted vegetable medley.