Make the marinade by combining the Greek yogurt, olive oil, lemon juice, minced garlic, minced oregano, minced thyme leaves, balsamic vinegar, lemon zest, salt, freshly cracked pepper, and crushed red pepper flakes together in a large zip lock bag.
Seal and massage the bag to combine the ingredients well. Add the chicken to the bag turning to coat then seal. Place into the refrigerator to marinate 4-24 hours making sure to turn the bag a few times while marinating.
Thread chicken pieces onto the skewers alternating with peppers and onions.
Cook the kebabs by heating the olive oil a large grill pan over medium-high heat until HOT.
Add the skewers and cook on all sides until golden brown, about 5-7 minutes on all sides, or until cooked through.
Remove from the grill pan sprinkle with fresh parsley and serve immediately. Enjoy.