Preheat oven to 350°F and coat a 9x13” baking dish with nonstick spray.

Bring a large pot of water to boil and cook pasta 1 minute shy of package directions. Drain pasta and rinse under cold running water. Set aside.

Melt butter in a large pot over medium heat. Add flour and whisk until combined. Let cook for 1 minute, whisking constantly. Add milk while whisking until mixture is smooth. Bring to a boil, stirring frequently, and cook until sauce has thickened.

Turn off heat and add cheeses, stirring until melted. Add seasoning, salt and hot sauce, and stir to combine. Gently fold in cooked chicken and cooked pasta.

Transfer pasta mixture to prepared baking pan and top with crushed crackers. Bake for 35 minutes, or until the center is hot and bubbly and the top is golden-brown. Garnish with scallions.