So how would you pronounce it..?

[kitkatvintage]

I would have thought Zan-iss, but only because I know someone with the name Xan & she pronounces it "Zan".

[Twizel]

I would say [Zan-ihss]. The only 'X' that I ever pronounced with an [Ex] was the name Xavier. And that was 100% because of X-Men: The Animated Series (best cartoon ever lol).