Rinse chicken; pat dry with paper towels. Spray an unheated 12-inch skillet with nonstick cooking spray. Preheat skillet over medium heat. Add the chicken and cook for 10 to 15 minutes or until lightly brown, turning to brown evenly and adding onion and garlic during the last 5 minutes of cooking. Add the potatoes and pumpkin or winter squash.
Combine wine or broth, rosemary, salt, and pepper; pour over chicken and vegetables. Bring mixture to boiling; reduce heat. Cover and simmer for 25 minutes. Add zucchini. Cover and cook about 5 minutes more or until chicken and vegetables are tender and chicken is no longer pink. Using a slotted spoon, transfer chicken and vegetables to a serving platter. Pass pan juices. If desired, serve with lemon wedges. Makes 6 servings.