Preheat oven to 425F.
In a bowl, whisk together, olive oil, vinegar, lemon juice, mustard, garlic, oregano, thyme, salt, and pepper.
Add chicken thighs to bowl and pour half of marinade over top. Mix until chicken is coated.
Add all veggies to sheet pan and pour remaining marinade over top. Stir to mix together until veggies are coated.
Tuck chicken thighs on and between veggies on sheet pan, they can be slightly overlapping veggies.
Bake for 15 minutes. Add feta, olives, and parsley over top of chicken and veggies. Bake for another 15-20 minutes. Once chicken temp reads 165F, take out of oven.
Let cool 10 minutes before serving.