Heat olive oil in large, heavy-bottomed skillet. Season chicken pieces with salt and black pepper and place, skin side down, in hot oil. Cook chicken until skin is golden brown, 6 to 8 minutes. Turn chicken pieces over and cook 3 to 5 more minutes. Remove chicken from pan and set aside.
Put onions in skillet and cook over medium heat until vegetables soften, about 10 minutes. Add mushrooms and cook until softened, 5 minutes. Return the chicken to skillet and add entire jar of sauce along with broth. Bring liquid to a simmer, cover, and cook for 20 to 25 minutes, turning chicken halfway through cooking time.
When chicken is cooked through (juices run clear when cut with a knife) remove from skillet and set aside, covered. Allow sauce to simmer, uncovered, for 5 to 10 minutes until slightly thickened. Serve cacciatore over cooked linguine with a fresh baguette.