If she was smart she would perform a new song and re release 1989, it's her biggest album and she should do everything in her power to make it memorable as possible. Kind of like Katy did with teenage dream.
Although she will most likely perform an album track as its too late for OOTW
"This Love" or "Clean" would be ideal for this. Although i'd love it if she performed the "Enchanted / Wildest Dreams" mash-up from the tour, but it seems unlikely!
