Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Dice the sweet potato into half-inch cubes and slice the carrots into thin rounds to ensure they cook at the same rate as the chicken.
Cut the chicken breast into bite-sized pieces and place them in a large mixing bowl with the sweet potatoes, carrots, and broccoli florets.
Mince the garlic cloves and add them to the bowl along with the olive oil, rosemary, thyme, sea salt, and black pepper.
Toss all ingredients together until the chicken and vegetables are thoroughly and evenly coated with the oil and herb mixture.
Spread the mixture in a single layer on the prepared baking sheet, making sure not to overcrowd the pan so the vegetables can roast properly.
Roast for 20 to 25 minutes, tossing the ingredients halfway through, until the chicken is cooked through and the sweet potatoes are fork-tender.