As long as there is a bar there, a Megatouch will be played and earn money. In nightclubs, not all people will dance and some will sit at the bar to BS, or to "scope out the action." You get a single person sitting there, and the Meatouch will make some money.
I agree that you will need a newer Megatouch, and the LCD ones don't take up much space. Older ones, even from 2005 or so, non-LCD but with a CRT, are not too expensive. I've seen some on eBay go for $500 or so.
To say if it would make good money or not, your best bet would be to go and see the nightclub, talk to the manager about the client base. If it's a popular 20-something hang out, I don't think it would fare the best. If it has a mixed client base, then you may be surprised.
Just my opinion on this matter, and from when I was bartending.
Bill