Prepare pasta to package directions for al dente. Drain (do not rinse), set aside.
Cut chicken breasts into cutlet sized pieces or strips. Salt and pepper both sides. Melt 2 tablespoons of butter in a large skillet on medium heat. Cook about 4 minutes on each side, until golden brown and the juices are no longer pink.
Transfer browned chicken to a plate and cover with foil.
In the same skillet, melt the additional butter over medium low heat. Stir in the shallots and fresh sage. Cook and stir frequently until the butter is golden brown and the shallots are tender and slightly brown.
It is important to watch the temperature and not let the butter burn, or else it will be bitter.
Reduce heat to low. Add the prepared pasta to the skillet and toss to coat. Cook for a minute or two until the pasta is warmed through.
Transfer the pasta to a large serving platter. Top with sliced chicken and additional sage if desired. Pour the juices from the chicken (from the plate where they were on) over the top.