In a medium bowl, whisk together the apple cider, Dijon mustard, brown sugar, soy sauce, garlic powder, onion powder, black pepper, and salt until well combined.

Place the chicken breasts in a large resealable plastic bag or a shallow dish. Pour half of the cider glaze over the chicken, ensuring all surfaces are coated. Seal the bag or cover the dish and refrigerate for at least 30 minutes, or up to 2 hours for more flavor.

Preheat your oven to 375°F (190°C). Remove the chicken from the marinade, allowing excess marinade to drip off. Reserve the remaining glaze for later use.

In a large oven-safe skillet, heat the olive oil over medium-high heat. Once hot, add the chicken breasts and sear for about 4-5 minutes on each side until golden brown.

Pour the reserved cider glaze over the chicken and sprinkle fresh thyme leaves on top. Transfer the skillet to the preheated oven.

Bake for 20-25 minutes, or until the chicken is cooked through and reaches an internal temperature of 165°F (74°C).

Remove the skillet from the oven and let the chicken rest for 5 minutes before slicing. Drizzle with any remaining glaze from the skillet before serving.