He is probably nippy because he hadn't been handled in a while and might not feel so well.

This is my opinion only, but with a snake like that the main thing you have to do is do what you would normally do--give him good caging, temps, humidity, and food. He will eat more than normal for a while when he starts accepting prey, but if he's not severely emaciated he will probably turn around fine when he gets what he needs.

I got one a couple of weeks ago that was dehydrated, carrying some stuck shed, needed some groceries, and mean as snot.

2 weeks later--well hydrated, stuck shed is off, still a little thin but picking up, and hissing, not biting.