Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Prepare the vegetables by cutting the carrots into 1/4-inch thick rounds and breaking the broccoli into bite-sized florets.
Dice the chicken breast into uniform 1-inch cubes to ensure even cooking.
In a large mixing bowl, combine the chicken cubes, broccoli florets, and sliced carrots.
Mince the garlic cloves finely and add them to the bowl along with the olive oil, rosemary, thyme, sea salt, and black pepper.
Toss the mixture thoroughly until every piece of chicken and vegetable is well-coated in the herb-infused oil.
Spread the mixture onto the prepared baking sheet in a single layer, ensuring they aren't overcrowded so they roast rather than steam.
Roast in the center of the oven for 20 to 25 minutes, tossing halfway through, until the chicken reaches an internal temperature of 165°F and the vegetables are fork-tender with caramelized edges.