Place large non-stick skillet over medium high heat with olive oil. Drain chicken and cook in skillet until all the pink is gone (you may have to do this in batches depending on how big your skillet is). Place cooked chicken in large bowl and season with salt and pepper to taste. Cover and refrigerate until cool, about 1 ½-2 hours.
In a small bowl mix together cream, mayonnaise, Greek yogurt, poppy seeds, and orange zest until combined. Pour mixture over chicken and season to taste with salt and pepper. Add chopped celery and mix until combined. Cover and refrigerate for at least 2 hours.
In a small pan over medium heat, melt butter. Add nuts and cook until toasted, about 2-3 minutes (they should be a little more than lightly browned and you’ll begin to smell them).
Stir in toasted nuts and dried Cranberries just before serving. Serve with split croissants.