Preheat the oven to 400°F (200°C).
Pat the chicken breasts dry with paper towels. Season both sides with 1 teaspoon kosher salt, 1/2 teaspoon black pepper, and 1 teaspoon garlic powder.
In a large oven-safe skillet, heat 2 tablespoons olive oil over medium-high heat until shimmering.
Add the chicken breasts to the skillet and sear without moving for 5 minutes until golden brown.
Flip the chicken breasts and add 3 tablespoons unsalted butter, 3 cloves minced garlic, and 1 teaspoon fresh thyme leaves to the skillet.
Spoon the melted butter and garlic over the chicken breasts as they cook for another 3 minutes.
Add the baby carrots and broccoli florets to the skillet around the chicken. Season the vegetables with 1/2 teaspoon kosher salt and 1/4 teaspoon black pepper.
Transfer the skillet to the preheated oven and roast for 7 minutes, or until the chicken reaches an internal temperature of 165°F (74°C) and the vegetables are tender.
Remove the skillet from the oven. Let the chicken rest for 3 minutes before serving, spooning the garlic butter sauce over the top.