Thats not how a nameserver works....
firstly you need a domain name any .com will do it has to be officially registered with a IEEE or IANA certified registrar. Once you have that you will have management options to set it up to point to name servers.
Your nameservers have to be where your site is hosted. HOWEVER! the problem is you have to make sure you add the domain to your hosted site. it took me ages to figure it out so for example if youve hosted it at wxyz servers most probably your name servers will be
ns1.wxyz.net
ns2.wxyz.net
etc....
but say your current domain your using or the hosting is at mysite.wxyz.net and you want your domain to go to there you have to put up lookup records in the back end through domain management.
so you have to add an A record to point
www.mydomain.com A mysite.wxyz.net
once you do that your domain successfully redirects to that host.
BUT WAIT Theres more!
you must also login to the CPANEL of your hosting service and Add on the domain you have registered.
in my personal opinion to save you all the hassle. Buy Hosting and domain at once and it will all be done for you! but if you know what your doing this is deffinently much cheaper.
i run 10 domains with one hosting and i pay like 10 bucks a month (AUD) and i paid about a dollar for each domain so its alot of money saved.
Complicated i know!
PM me if you need more info. lol