Hey I don't read x-men apart from x-23 but would like a good story arch or one shot that focuses on nightcrawler without having to know the ins and outs of x-men.

AOA - good question.  Nightcrawler was my #1 character that got me into comics.  But, sadly, there aren't a ton of great stories for him outside of bigger team-focused tales. 
  
ONE-SHOTS:
X-Men: Origins - Nightcrawler was a pretty good one-shot recently.   I would also recommend one of the first comics I wrote - awkwardly titled X-Men: Manifest Destiny - Nightcrawler.  It got a little muddled in its journey from proposal (a miniseries) to its ultimate fate (a one-shot with a few mandated changes).  But I would say that if you like Nightcrawler, you should enjoy the center 80% of the book.   
 
As for single-issues:  maybe Excalibur #31 & Uncanny #204
 
MINISERIES: 
There was a solid (if surprising) limited series in 2004 just titled Nightcrawler that lasted 12 issues.  The first few issues aren't great, but the series improves as it goes along.  I don't think you'd 'miss' anything if you got issues 7-12 of that one.   
 
STORY ARCS: 
My personal favorites would be the ones that got me hooked in the first place - early issues of Excalibur and the #122-165-ish range of Uncanny X-Men.  Some of the later Excalibur stuff is good (I'd consider either the Alan Davis or Warren Ellis collections) - and certainly a more modernly paced reading experience.   
 
AVOID: 
Chuck Austin's X-Men stuff.   -  Unfortunately, one guy who actually spent time on Nightcrawler was one of the most widely reviled runs on the book.  I approached it with an open mind, but did not enjoy those books at all. 
The first Nightcrawler mini (from the mid-80s) is pretty cartoony and, IMHO, doesn't hold up well.   He had a four-issue mini in the early 2000s that was bone dry and not particularly rewarding.  

An old limited series. Ancient.

He's had a couple of mini-series in the past, but none of them have been particularly interesting or well-written, much to my dismay.