Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
In a small bowl, combine the buttermilk with garlic powder, paprika, salt, and black pepper.
Place the chicken breast in a shallow dish and pour the buttermilk mixture over it. Allow it to marinate for at least 15 minutes, turning the chicken to coat evenly.
In another bowl, spread out the panko breadcrumbs.
After marinating, transfer the chicken to the breadcrumb bowl and press lightly to coat all sides.
Arrange the breadcrumb-coated chicken on the prepared baking sheet.
Chop broccoli, carrot, and zucchini into bite-sized pieces. Toss them with olive oil, a pinch of salt, and additional pepper if desired.
Place the vegetables around the chicken on the baking sheet, ensuring they are in a single layer.
Bake for 20-25 minutes, or until the chicken reaches an internal temperature of 165°F (75°C) and the vegetables are tender and slightly crisp.
Serve warm and enjoy your nutritious, crispy baked chicken with roasted vegetables.