Preheat oven to 375°F.

Add chicken breast to a small lidded saucepan. Fill with cool water to cover and add a generous pinch of salt. Bring to a boil and then reduce to a low boil. Cover with a lid and cook for 12-15 minutes or until internal temperature reaches 165°F.

Shred the chicken on a cutting board with two forks. Be sure to finely shred for best results.

Meanwhile, bring a large pot of salted water to a boil. Cook elbows until al dente. Strain and set aside.

With chicken and macaroni boiling, melt butter over medium-low heat. Add the flour, 1 tablespoon at a time, whisking constantly until incorporated and roux has formed, about 1-2 minutes.

Slowly whisk in warm milk, one cup at a time, whisking out any lumps if they form. Heat until the sauce just starts to bubble in the center. The sauce should be smooth and creamy and will have a similar consistency to thickened gravy. Whisk constantly to prevent burning.

Add half of the cheese to the skillet and whisk until nearly all is melted and smooth. Add the remaining cheese and whisk until smooth. Add the buffalo sauce and mix until fully incorporated.

Stir in cooked elbows and shredded chicken until evenly distributed. This may be easiest in batches so the pan isn't overcrowded.

Melt 1-2 tablespoons of butter in a small bowl. Stir in panko crumbs until thoroughly mixed. Top mac and cheese with buttered panko crumbs. Bake for 10 minutes or until the panko crumbs are golden. Serve immediately.