Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Slice the zucchini into half-moons, chop the red bell pepper into 1-inch pieces, and thinly slice the red onion.
Mince the garlic cloves finely.
Place the chicken breast and all the chopped vegetables onto the prepared baking sheet.
Drizzle the extra virgin olive oil and lemon juice over the chicken and vegetables.
Evenly sprinkle the minced garlic, dried oregano, sea salt, and black pepper over the ingredients.
Toss everything thoroughly with your hands or tongs to ensure an even coating of oil and spices, then spread into a single layer.
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 caramelized edges.
Remove from the oven and let the chicken rest for 5 minutes before slicing into strips.
Serve the sliced chicken alongside the roasted vegetables, drizzling any remaining pan juices over the top.