In the movie Mad Max: Fury Road (2015), far almost half of the movie, Nux's motive is to kill Furiosa, return the wives to Immortan Joe and get a fair reward from him, Nux mentioned it from his words.
During the chasing scene, with the help of Joe's crew, Nux gets on top of war rig and tries to kill Furiosa but he gets restrained by a chain and couldn't achieve killing her, so, Joe calls him a mediocre.
My question, why all of a sudden he turned into a good guy by helping Furiosa and Max? If he wants to become a great war boy and impress Joe, he could still do it by freeing himself from the restraint, but in the next scene, he becomes so soft with one of the wives and starts helping Furiosa. Any reason for him to change his mind that I missed?