MAN THE POSSIBILITIES ARE ENDLESS.
I believe that Minato will tell Naruto more about is family(Mother, Father, Heritage), Bloodline treats(key to unlocking Naruto's jutsu creation potential), reason for putting 9tails within him, and possibly how to control the 9tails.
I hope Minato teaches Naruto 'Flying Thunder God' because with naruto's chakra he could create 1000 clones and preform the 'FTG' and destroy whole army's without having to fighting himself. His aggressive fighting style would be maximized .
this is the beginning of a possible new chapter in young Naruto's life, he may receive his final lesson, and hear words like these "Naruto we can teach you no more" everyone asked who would be naruto's teacher now. Well, we have been given a possible answer Minato the 4th, the greatest and most talented ninja the leaf has ever produced before Naruto, and he's naruto's father.