Place the chicken thighs and 1 cup stock in a baking dish. Turn oven to 400F. Salt the thighs, and place ½ tablespoon butter on top of each piece of chicken. Roast until cooked through, for 50 minutes. Remove to a plate to cool, reserving the juices.
While the thighs are cooking, cook and drain the pasta 2 minutes before al dente. Whir the Cheez-Its in a food processor or crush in a plastic bag until coarse crumbs form.
When the chicken thighs and pasta are cooling, make the sauce: add the remaining 2 tablespoons butter to a large pot (the same one you used to cook the pasta is good!) over medium heat. When the butter is melted, add the flour and whisk for 1 minute to create a thin roux. Add the beer, drippings from the chicken pan, and the half and half. Whisk, and increase the heat on the pot to medium-high. Let the mixture come to a bubble, and add more stock as needed to make about 3 cups total, including the beer, stock, and half and half.
Add the paprika, garlic, nutmeg, and ⅔ of the grated cheese to the pot. Stir until the cheese is melted, then turn off. Shred the chicken with your fingers or two forks into bite-sized pieces.
To the cheese sauce, add the pasta, chicken, and remaining cheese. Stir to combine, then taste - add salt to your preference. Pour into a baking dish - I used the same one I used to braise the chicken. Top with the Cheez-it crumbs, then bake at 450F until bubbly and slightly browned on top, about 15 minutes if you cook the mac right away.
Enjoy!