01 - Preheat oven to 350°F.
02 - Slice the top off the sourdough loaf and hollow out the center, leaving a 1-inch thick shell. Reserve the removed bread for dipping.
03 - In a large bowl, combine the shredded chicken, cream cheese, buffalo sauce, ranch or blue cheese dressing, mozzarella, blue cheese (if using), cheddar, and most of the green onions. Mix until well blended.
04 - Spoon the mixture into the hollowed-out bread bowl. Place the bread bowl on a baking sheet.
05 - Bake for 25-30 minutes, until the dip is hot and bubbly and the cheese is melted.
06 - Sprinkle with remaining green onions. Serve hot with celery, carrots, tortilla chips, and reserved bread cubes for dipping.