Combine onions and garlic in oil, saute a few minutes; remove from heat.
Season thighs with salt, pepper,garlic poweder and oregano; cook in a medium hot skillet about 2-3 minutes until they are golden brown, turn over, add onion & garlic mixture,lemon juice and zest and 1 T. parsley, cook another 3 minutes.
Place chicken in a baking dish, top with olives and tomatoes.
Roast 15-20 minutes until chicken juices run clear.
Remove from oven; top with parsley and feta cheese, serve.