Preheat the oven: Heat to 375°F (190°C). Lightly coat a 9-inch baking dish or similar with cooking spray.
Mix the base: In a large bowl, stir together the softened cream cheese, Greek yogurt, buffalo sauce, ranch seasoning, and lemon juice.
Mix until smooth.
Add the chicken and cheese: Fold in the shredded chicken, green onions, blue cheese (if using), and 1/2 cup of the shredded cheddar. Season with pepper.
Transfer and top: Spread the mixture evenly in the prepared baking dish. Sprinkle the remaining 1/2 cup shredded cheese on top.
Bake: Bake for 18–22 minutes, until hot and bubbling around the edges and the cheese is melted.
Broil for a golden top (optional): Broil on high for 1–2 minutes to lightly brown the cheese.
Watch closely.
Garnish and serve: Let it cool for 5 minutes. Top with extra green onions. Serve with celery sticks, carrot sticks, sliced cucumbers, bell pepper strips, tortilla chips, or whole-grain crackers.