Gather all ingredients and shred the cooked chicken if not prepped, ensuring you have about 3 cups. Soften the cream cheese at room temperature for 30 minutes.

In a large crockpot, combine the shredded chicken, softened cream cheese, ranch dressing, and buffalo sauce. Add the shredded cheddar and mozzarella cheeses, along with garlic powder and black pepper. Mix thoroughly.

Cover the crockpot and cook on low for 2 to 3 hours, stirring every 30 minutes.

Once cooked, stir the dip and garnish with chopped green onions. Serve with tortilla chips, celery sticks, or crackers.

Cool any leftovers, transfer to an airtight container, and refrigerate for up to 4 days.