Preheat oven to 450 degrees. Place the skillet in the oven to heat.
Combine thyme, garlic, orange zest, kosher salt and black pepper in a small bowl. Toss to combine.
Place the chicken, breast side up on a cutting board or baking sheet. Lay the chicken flat and using your hands, press firmly on the breast to flatten it out. Coat both sides of the chicken with olive oil and then sprinkle with the herb mixture. Rub the herbs into the chicken with your fingers.
Using a pair of oven mitts, remove the skillet from the oven and place on the stove. Transfer the chicken, breast side down to the hot skillet and return to the oven. Cook for 25 minutes.
Remove from the oven and carefully flip the chicken in the pan. Scatter the onions, orange sements and kalamata olives around the chicken and return to the oven. Cook for an additional 20 minutes.
Remove from the oven and transfer the chicken to a cutting board. Carve the wings, and legs from the chicken. Cut the breasts in half. Transfer chicken pieces to a platter. Serve with onions, oranges, olives and pan juices.