Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper for easy cleanup.
Peel the carrots and slice them into 1/2-inch thick diagonal rounds to ensure even roasting.
Pat the chicken breast completely dry with paper towels and place it on one side of the prepared baking sheet, with the carrots on the other side.
In a small glass bowl, whisk together the olive oil, maple syrup, sea salt, black pepper, and garlic powder until well combined.
Drizzle the maple mixture over both the chicken and the carrots, using a brush or clean hands to ensure the chicken is fully coated and the carrots are tossed well.
Place the sheet in the oven and roast for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F.
During the last 5 minutes of roasting, scatter the pecan halves onto the baking sheet to lightly toast them and develop their nutty aroma.
Remove from the oven, let the chicken rest for 5 minutes before slicing, and garnish the entire dish with fresh thyme leaves before serving.