Derived from a cross between "how's it," with the suffix zah attached, which is another form of the suffix zor. Except that "zor" may be used to indicate a plural, while "zah" is only used in the singular.
The suffix "zah" originated in chat rooms, while phonetically typing with an accent. A prime example of this accent can be found in the song "IM the Supervisor" from the famed techno artist Infected Mushroom, in which the vocalist says "I'm the supervisor" repeatedly, making it sound like soop-uh-vi-zah.
P2: nm, u?
P1: just playin some gamezor.