Preheat oven to 350°.
Boil chicken and cube or shred. (You could cut up before you boil, but I do it after. And, I almost always use my Kitchen stand mixer to shred the chicken.)
To the chicken add the cream of chicken, the cream of mushroom and the sour cream and stir to combine.
In a microwave safe dish, melt the butter. To the butter add the crushed crackers, and the poppy seed.
Sprinkle about half of the cracker mixture on the butter of a greased 9x12 baking dish. Then add the chicken mixture. Finish with the remaining cracker mixture over the top.
Bake for 25 to 30 minutes.