Hmmm, I've smoked plenty of chickens. I typically prepare a brine and inject with an orange juice base that has brown sugar, then smoke with hickory. It doesn't really give much of a sweet flavor though, just juicy and enhances the natural flavor of the chicken.
I'd think your best bet for sweet on the tongue would be your dressing ingredients. If you're thinking of a mayonnaise dressing you could add a little apple cider, diced apples, sliced grapes, sliced sweet pickles and a little sweet pickle juice, plus pecans to your mayonnaise dressing. Our smoked chickens never end up in chicken salad but that's how we did leftovers from a smoked turkey last Thanksgiving. It was fantastic and the smoke really enhanced the salad. My wife does it and she never measures. She does the same thing with Costco canned chicken breast for a quick meal.