In a large bowl, cut up your chicken ( you can use plain chicken or herb roasted), toss in your chopped celery, cream of mushroom soup, water chestnuts and and mayo. Mix well and spread in a 9 x 11 sprayed casserole dish or tin. Spread evenly. Sprinkle stuffing on top and cut up your stick of butter and spread on top of stuffing. I would also spray the top with your butter spray. You can add a dab of water on the stuffing if you are tempted, I did:) I found even with the stick of butter the stuffing was still dry in some areas, so adding some water will help. It certainly was not a big deal either way.
