Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
In a small ramekin, whisk together the olive oil, sea salt, black pepper, dried rosemary, dried thyme, and garlic powder to create an herb paste.
Pat the spatchcock chicken dry with paper towels and place it on the prepared baking sheet.
Rub the herb paste evenly over the chicken, focusing primarily on the breast area to ensure deep flavor infusion.
Roast the chicken in the center of the oven for 35-45 minutes, or until the internal temperature of the breast reaches 165°F (74°C).
During the final 10 minutes of roasting, add the pre-cooked sweet potatoes to the baking sheet to allow them to warm through and develop a slight outer crisp.
Remove the chicken from the oven and let it rest for at least 5 minutes before carving to allow the juices to redistribute.
Measure out 7.5 ounces of the roasted breast meat, removing the skin to keep the meal within your calorie targets, and serve alongside the warmed sweet potatoes.