Nhan? I'm assuming that sounds like 'non', so it's probably easier to use your real name. I do know some people who abbreviate their names, though, if there's a workable abbreviation (e.g. Siddahrta / Sid).
To me, when listening to that, it sounds like "Nyen" or "Nian", which isn't a sound that any English word I can think of correlates with an H. Perhaps sharing one of these spellings with people will help them. You might experiment with different people and see where you get your best results.
