Preheat oven to 375°F (190°C).
Cook pasta according to package directions, cooking al dente. Reserve 1 cup of pasta water before draining.
In a large bowl, combine hot sauce, melted butter, Worcestershire sauce, cayenne pepper (if using), and minced garlic. Add shredded chicken and toss to coat.
In a saucepan, melt butter over medium heat. Whisk in flour and cook for 1 minute, creating a roux. Gradually whisk in milk until smooth. Bring to a simmer, stirring constantly, until thickened. Remove from heat and stir in cheddar cheese and mozzarella cheese until melted and smooth.
Add cooked pasta and buffalo chicken mixture to the cheese sauce. Stir to combine. Add reserved pasta water if sauce is too thick.
Grease a 9×13 inch baking dish. Pour pasta mixture into the baking dish and spread evenly. Top with remaining cheese and blue cheese crumbles (if using).
Bake for 20-25 minutes, or until the cheese is melted and bubbly and the top is golden brown. Let rest for 5-10 minutes before serving. Garnish with green onions or parsley (if using).
