Buffalo Mac and Cheese

• 1 (16 ounce) package elbow macaroni
• 1 rotisserie-roasted chicken
• 6 tablespoons butter
• 6 tablespoons all-purpose flour
• 3 cups milk
• 1 pinch ground black pepper
• 2 cups shredded Cheddar cheese
• 2 cups shredded Monterey Jack cheese
• ½ cup hot sauce (such as Frank's® Redhot®), or more to taste
• ½ cup crumbled gorgonzola cheese