Preheat the oven to 350°F. Lightly grease a 11- x 7-inch baking dish. Remove the skin from the chicken. Shred the chicken into bite-size pieces. (Equals about 3½ cups.)
Whisk together the cream of chicken soup, sour cream, and onion powder in a large bowl. Fold in the chicken until well combined. Spoon the mixture into the prepared baking dish.
Stir together the crackers, melted butter, and poppy seeds in a medium bowl until combined.
Sprinkle the cracker mixture evenly over the chicken. Bake for 30 minutes or until the filling is bubbly and the crackers are golden brown.
Remove the pan from the oven and serve over cooked rice, if desired.