12-ounce boneless skinless chicken breast (one large half breast or two small), cut into small cubes
1/4 teaspoon salt
3/4 cup Louisiana-style hot sauce (plus more for serving)
2 tablespoons butter
2 ounces crumbled blue cheese
3 large scallions, both the white and green parts, sliced thin
Bring a large pot of salted water to a boil over medium-high heat and cook noodles until al dente, about 12 minutes or according to directions on the box. Drain and reserve for later.
In a large pot set over medium heat, melt butter. Add flour and whisk to combine, stirring occasionally, for about two minutes or until golden. Whisk in milk, then increase heat to high, whisking constantly as the mixture thickens and comes to a simmer. Reduce heat back to medium, add salt and American cheese. Whisk for about a minute, until American cheese is fully melted, then add Jack cheese, whisking for an additional two minutes until the sauce is smooth and velvety. Add noodles directly to the sauce, and stir with a wooden spoon for about two minutes or until the noodles have soaked up some of the sauce.
In a large pan set over medium-high heat, heat the vegetable oil. When the oil shimmers, add chicken pieces seasoned with salt, and sauté until fully cooked, about five minutes. Turn the heat to medium, and add butter and hot sauce. Stir the mixture together and continue to cook for about 3 seconds, until the chicken has soaked up some of the buffalo sauce.
Transfer the macaroni and cheese to a baking dish, and add chicken on top, evenly distributing the buffalo sauce across the surface. Top with blue cheese crumbles and broil on low for 10 minutes, until the blue cheese is browned and melty. Remove from the oven, garnish with scallions and more hot sauce.