Preheat your oven to 425°F (220°C) and line a sheet pan with parchment paper.
Cut the sweet potato into 1/2-inch cubes and chop the broccoli into florets.
Place the chicken breast, sweet potato cubes, and broccoli florets on the sheet pan.
In a small bowl, whisk together olive oil, lemon juice, dried thyme, dried rosemary, garlic powder, salt, and pepper.
Drizzle the lemon herb mixture evenly over the chicken and vegetables, ensuring everything is well coated.
Arrange the ingredients in a single layer for even roasting.
Roast in the preheated oven for 20-25 minutes, or until the chicken is cooked through and the vegetables are tender and slightly caramelized.
Remove from the oven and let rest for a few minutes before serving.