Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
In a small mixing bowl, whisk together the extra virgin olive oil, lemon juice, minced garlic, dried oregano, sea salt, and black pepper to create the marinade.
Slice the zucchini into rounds, chop the red bell pepper into bite-sized pieces, and cut the red onion into thick wedges.
Place the chicken breast on one side of the prepared baking sheet and arrange the zucchini, peppers, and onions on the other side.
Drizzle the lemon-herb marinade over both the chicken and the vegetables, using your hands or a brush to ensure everything is evenly coated.
Roast in the center of the oven for 20-25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender with slightly charred edges.
Allow the chicken to rest for 5 minutes before slicing it into strips.
Serve the chicken and roasted vegetables together, finished with a sprinkle of crumbled feta cheese.