NLZ is an acronym for: No Life Zone. NLZ is used to describe one who has no life and the area that they are having no life in. Like for example: In his/her room in front of the computer all day is one, another is their play room playing PS3 all day.
Nick: Where is Kris? Is he going to hang out with us tonight?
Bob: No dude he is in his NLZ, and won't hang out with us the whole weekend!
Nick: Wow, he has no life hahaha.
Bob: True that man.