Heat the oven to 350°F. Line a rimmed baking sheet with a nonstick silicone baking mat, parchment paper, or aluminum foil.
Scatter the green beans and tomatoes on the prepared baking sheet in an even layer.
Place the chicken breasts on the baking sheet adjacent to the vegetables. Set aside.
Combine the buttermilk and Creole Ranch Dressing. Spoon the mixture over the top of the chicken breasts to coat.
Sprinkle over the panko breadcrumbs. Season the chicken and vegetables with Creole Seasoning.
Spray entire pan with nonstick cooking spray.
Transfer to the oven until bake and the vegetables are tender and the chicken is cooked, about 20 minutes. (An instant read thermometer will register 165°F when inserted into the breast.)
Remove from the oven and serve immediately.