He's actually a Belgian actor, that has lived in both Britain and Canada. If he's undercover, it is possible they could say, as he was undercover, that he was putting on an accent? Or he's lived around the world? I'm not saying he is Chic - it was someone else's theory - but there definitely does seem to be more to him than meets the eye, so him being FBI is a possibility and Chic in the comics was undercover FBI.
The only thing that bothered me about Chic possibly not being Chic was how he knew who Betty and Alice were and the similarities between his and Betty's 'darkness'. However, looking back, Betty pretty much volunteers info on some of her issues and if he isn't the real Chic but did know the real one, he could have surmised that she would have similar problems and copied them. Also, Betty found him very easily, so he could have found them the same way. If he adopted the identity of Chic - (maybe with some twisted idea of revenge/jealousy/obsession or just pure identity theft because he was on the run or something???) - and if the real Chic was often off the grid, undercover, adopting his identity probably could have gone unnoticed for a while - especially as the name Charles Smith isn't that uncommon. You add Smith to any name and there would usually be many others.