1. Preheat your oven to 400 F (200 C). Line a large baking sheet with parchment paper for easy cleanup.

2. Cut the boneless, skinless chicken breasts into uniform 1-inch pieces. Chop your chosen mixed vegetables into similar-sized pieces so everything cooks at the same rate.

3. In a small bowl, whisk together the olive oil, fresh lemon juice, minced garlic, dried oregano, dried thyme, salt, and black pepper.

4. Place the cut chicken and chopped vegetables on the prepared baking sheet. Pour the lemon-herb dressing evenly over the chicken and vegetables. Use your hands or a spatula to gently toss everything together, ensuring all pieces are well coated. Spread them out into a single layer on the baking sheet. Avoid overcrowding the pan; if necessary, use two baking sheets.

5. Transfer the baking sheet to the preheated oven. Roast for 20-25 minutes, or until the chicken is cooked through (internal temperature reaches 165 F / 74 C) and the vegetables are tender-crisp and slightly caramelized. You can gently stir the mixture halfway through cooking for more even browning.

6. Once cooked, remove the baking sheet from the oven. If desired, sprinkle with fresh chopped parsley for a burst of color and fresh flavor. Serve immediately and enjoy your healthy, delicious meal!