Heat oil in a skillet over medium-high heat. Reduce heat, and cook chicken, turning once, until no longer pink in center and juices run clear. Set aside to cool.
Preheat oven to 350 degrees F (175 degrees Celsius).
Cut chicken into bite size pieces, and place in a bowl with the cream of chicken and mushroom soups, and the sour cream. Stir until well blended, then transfer mixture to a 9x13 inch shallow baking dish. In a separate bowl, combine the crushed crackers
with the poppy seeds. Melt butter in the microwave for 30 seconds, or in a small saucepan over low heat. Stir butter into the cracker mixture, and spread evenly over the chicken.
Bake chicken in the preheated oven for 30 minutes, or until heated through and lightly browned on top.