I love these sandwiches! I started eating them back when Arby's came out with them a few years ago and just make my own version at home. You don't have to heat up the house and they are quick and versatile, I just throw in whatever ingredients I happen to have.
The base is cooked chicken. Use your own that you've precooked, use rotiserrie, or use canned. This time I used one can of chicken and shredded it good. Then I added around 1/2C mayo. I used 1 green onion, finely chopped and 1 celery stalk, finely chopped. Add in as many grapes as you like and cut them in halves, I used around 1C of grapes. If you don't want grapes, you could use craisins or raisins. I diced up an apple and threw it in. I like walnuts on my sandwich, but no one else does, so I throw some walnuts on mine at the end. Mix everything well and spread onto a croissant, or bread, or a tortilla.
Easy! and very Good!