Preheat your oven to 400°F (205°C) and line a large baking sheet with parchment paper.

In a large bowl, toss the cubed sweet potatoes with 2 tablespoons of olive oil, 1 teaspoon garlic powder, ¾ teaspoon salt, and ¼ teaspoon pepper until evenly coated. Spread them in a single layer on half of the prepared baking sheet, making sure they aren't crowded.

Using the same bowl, combine the chicken breasts with the remaining 2 tablespoons olive oil, maple syrup, apple cider vinegar, ½ teaspoon garlic powder, ¾ teaspoon salt, ¼ teaspoon pepper, and fresh thyme. Toss until the chicken is thoroughly coated with the glaze mixture.

Arrange the glazed chicken breasts on the other half of the baking sheet, leaving space between each piece for even roasting. Place the pan in the oven and roast for 25-30 minutes until the chicken reaches 165°F internally and the sweet potatoes are fork-tender with golden brown edges.

During the last 10 minutes of roasting, melt butter in a small skillet over medium heat. Add the chopped pecans and toast for 3-4 minutes, stirring constantly until they smell nutty and turn golden brown. Remove from heat immediately.

Once the chicken and sweet potatoes are done, remove the baking sheet from the oven. Let the chicken rest for 3-5 minutes, then sprinkle the toasted pecans over the sweet potatoes.

Transfer everything to a serving platter and garnish with freshly chopped parsley. Serve immediately.