You should be able to go into the $1 chip denomination category. That will cut down some of the noise, but of course there's always a chance that a gem is misfiled. Then start to fill in some of the search terms you are looking for (NV, LV, Las Vegas, Nevada) and maybe that will cut it down some more. I've noticed that most people for NV chips will put that somewhere in the title or description.

But even doing that some sneak through the other way...

http://desc.shop.ebay.com/i.html?_nkw=LV%2C+NV%2C+%22Las+Vegas%22%2C+Nevada%2C+&_in_kw=2&_ex_kw=&_sacat=63750&_okw=LV%2C+NV%2C+%22Las+Vegas%22%2C+Nevada%2C+&_oexkw=&LH_TitleDesc=1&_udlo=&_udhi=&_ftrt=901&_ftrv=1&_sabdlo=&_sabdhi=&_samilow=&_samihi=&_sadis=200&_fpos=Zip+code&_fsct=&LH_SALE_CURRENCY=0&_sop=12&_dmd=1&_ipg=50&_rdc=1