I love it, but would use Art as the nickname. Most people I know whose DC have nicknames tend to use the full name when they've done something really wrong. If you can happily picture yourself yelling 'NO Moriarty, don't do that!'in a crowded supermarket then go for it, if that gives qualms keep thinking.
I didn't use one of the names I really liked for DS1 as I was worried about school and teasing, someone at his school has that name and isn't teased at all so obviously it was a non-issue really.