Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Peel and dice the sweet potato into 1/2-inch cubes, and chop the broccoli, bell pepper, and zucchini into uniform bite-sized pieces.
In a small mixing bowl, whisk together the extra virgin olive oil, lemon juice, minced garlic, dried rosemary, dried thyme, sea salt, and black pepper.
Place the chicken breast and all the chopped vegetables onto the prepared baking sheet.
Drizzle the lemon-herb marinade over the chicken and vegetables, tossing thoroughly with your hands or tongs to ensure everything is well-coated.
Arrange the ingredients in a single layer, placing the chicken breast in the center of the tray surrounded by the vegetables.
Roast in the oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and slightly caramelized.
Remove from the oven and let the chicken rest for 5 minutes before slicing it into strips and serving alongside the roasted vegetable medley.