Khan by KO. I actually think it could end up looking like Khan-Salita. Maidana can't take a punch either (how many times did Ortiz drop him?)
But there's also the possibility that Maidana drops a right hand on Khans chin and KOs him.
60/40 Khan by KO
I'll take Maidana by KO. People might say "But Kotelnik beat Maidana and Khan beat Kotelnik" but that's no way to predict fights. Kotelnik won a razor thin decision and Maidana is a better fighter now. Styles make fights. I don't think Khan has the chin or stamina to do what Kotelnik did.
If Maidana hits him clean. He wins.
In my opinion Maidana only has a puncher's chance, which is still a fair chance bearing in mind his power and Khan's chin.
But I still expect Khan to be good enough to evade him and win comfortably.