Cook a little over half the bag of egg noodles until done.
In a bowl,combine the chicken, cream of chicken soup, and sour cream. Mix well.
In a 9x13 take a small chunk of cold butter and rub the bottom of the pan. This insures that the noodles will not stick or become crispy. (I find that this is the only way that works for me. Using spray Pam has always made my noodles on the side crispy.)
Spread noodles over greased pan.
Spread the chicken mixture on top making sure to cover all the noodles well.
Melt the stick of butter and crumble the whole package of Ritz crackers in it and mix until crackers are saturated. Spread on top of chicken mixture.