Djokovic is probably at his peak right now, having won 3 majors in 2015 and many think it is very possible that he could go on to eclipse not only Nadal's major total of 14, but possibly even Roger Federer's at 17. I doubt Djokovic will get that far, but I do suspect his final major total will be in the "teens."
If Djokovic wins it will be his 56th career ATP title (currently 55-26) while if Nadal wins it will be his 68th career title (67-29). Djokovic is trying to win his 6th China Open title (5-0) while Nadal is trying to win his 3rd (1-1). Djokovic beat Nadal in straight sets to win the 2013 title.
MadProfessah's pick: Djokovic.