Mix the herbs, mustard and olive oil in a nonreactive baking dish. Add the chicken, season with salt and pepper and turn to coat evenly. Cover and marinate in the refrigerator at least 1 hour or overnight.
Preheat the oven to 450 degrees F. Place the chicken on a foil-lined baking sheet and roast until the meat is cooked through and the skin is crisp, 30 to 40 minutes.
Meanwhile, saute the bacon in a deep pan or Dutch oven over medium heat until rendered, about 5 minutes. Add the onion and cook until translucent, 6 to 7 minutes. Add the greens, in batches, and saute until wilted, about 4 minutes. Add the chicken stock, cover and gently braise over low heat until tender, about 40 minutes. Season with salt and pepper and serve with the chicken.