Pound the chicken breasts evenly, then place them in a plastic zipped top bag or large bowl.
In a small bowl, whisk together the olive oil, lemon juice, garlic, oregano, salt and pepper. Pour the marinade into the bag with the chicken, seal and massage into the chicken, then refrigerate for at least 1 hour, up to 4 hours.
When ready to cook, preheat the oven to 400 degrees Fahrenheit. In a large cast iron skillet set over medium-high heat, heat 2 tablespoons of olive oil.
Remove the chicken from the marinade and place it in the hot skillet; discard the marinade.
Sear the chicken, 2 to 3 minutes on each side. Add the white wine and deglaze the pan, then add the chicken broth and simmer, reducing the liquid by half. Remove the skillet from the heat and transfer the chicken to a cutting board.
Place half of the artichoke hearts, tomatoes, olives and onion, in the bottom of the skillet, then place the chicken on top. Tuck the remaining vegetables around the chicken. Cover with a lid or foil and bake for 20 to 25 minutes, or until the internal temperature of the chicken reaches 165 degrees Fahrenheit on an instant thermometer.
Remove from the oven and sprinkle with sun-dried tomatoes and feta cheese. Bake, uncovered for another 5 minutes.
Allow to rest 5 minutes before serving. Garnish with lemon slices and fresh parsley.
STORAGEStore leftovers in a sealed container in the refrigerator for up to 3 days. To freeze, you can add this chicken dinner to an airtight container or freezer safe bag, making sure to remove all of the air. Freeze for up to 3 months. The tomatoes may not hold their shape as well when defrosting but it will still taste delicious.To reheat, warm in the microwave or in a skillet over medium heat until heated through.