There is some debate on the best typing to turn into. Fighting is okay, however shares a weakness to fairy as of gen 6 so is rendered obsolete. Not saying it's a bad idea, but Zoroark is built like Alakazam. It's fast and hits hard but one strong hit and your streak is done. Personally Zoroark in my opinion outclasses Alakazam because of its ability and typing. 1 misplay is GG. Poison is a good typing and probably the best option in my opinion. Naganadel, Toxapex, and Nihilego are big on the board so having one in your corner is always a good option in case your sweep ends suddenly. It resists all of Zoroark's weaknesses so unless it's boosted you'll likely survive to get a nasty plot in and start cleaning house.
I run Zoroark typically with Sableye as I can render physical threats useless with will o wisp then send out Zoroark as my win condition. Poison is also good as you'll be less likely to be Toxic as well. Ultimately you just have to pay attention to plays, especially in ou as Lele is a threat to Zoroark. As such Nihilego will be a good illusion because Lele doesn't wanna go down to a sludge wave and as Nihilego is specially defensive it'll take the hit. So easy switch out, free nasty plot. Watch out for psyshock though.
If you want another option for typing, ghost is good as it resists all it's weaknesses as well and be less likely to be hit by a physical fighting move. Chandelure, Alolan Marowak, Drifblim are good for this, or get the best of both worlds with Gengar
Pro tip, most people I see on showdown run focus sash as they get used to play then switch to choice scarf and trick with experience as usually they have a bug and fighting check so it makes room for Trick, however, darkinium z can be a good Trump card after a nasty plot.