Slice the chicken breasts in half lengthwise (butterflying), but cut through completely so that you have two thin chicken cutlets from each chicken breast.
Using a meat mallet, pound the chicken cutlets until ½ inch thick.
Heat a large nonstick skillet over medium heat for 5 minutes and add a thin layer of oil. Continue to heat for another 30 seconds.
Season both sides of the chicken with a pinch of salt and pepper. Sear the chicken on both sides for 4 minutes per side, or until golden brown and cooked through. You may need to work in batches as to not overcrowd the skillet. Remove chicken from skillet when done.
In a small bowl, combine the Greek yogurt, salt, pepper, chives, lemon, garlic powder and broth. Whisk well to combine.
Turn the skillet to medium-low and add the sauce, stirring frequently, for a few minutes. Spoon the sauce over the chicken when ready to eat.