Preheat oven to 400 F. Spray a roasting pan or large baking dish with non-stick cooking spray.
Place the chicken thighs in the base of a roasting pan or large baking dish. Add the baby potatoes around the chicken.
In a small mixing bowl, whisk together the olive oil, Dijon mustard, vinegar, garlic powder, chopped chives. Pour over the chicken and potatoes. Season with salt and pepper.
Roast in the preheated oven for 45 to 55 minutes, or until chicken is cooked through and potatoes are soft.
Prepare veggies.
Serve Roasted Chicken with Mustard-Chive Sauce, potatoes and veggies.