1. Preheat oven to 450°.
2. Combine parsley, chives, olive oil, Dijon mustard, and garlic in a small bowl, stirring well with a whisk. Rub herb mixture evenly over meaty side of chicken thighs; sprinkle evenly with salt and pepper.
3. Arrange chicken on a baking sheet or jelly-roll pan coated with cooking spray. Bake at 450° for 25 minutes or until done.
4. Preheat broiler to high (do not remove pan from oven). Broil chicken for 3 minutes or until browned.