>>26666137X&Y is universally agreed upon to be the hardest game in the main series to Nuzlocke.
Anybody who is a part of the nuzlocke scene will tell you this. There's so many stupidly difficult trainers/encounters scattered around that can easily either wipe your entire team or take 2-3 mons.
I never had nearly as much trouble nuzlocking any of the other games tbqh.
Oh and Gen 6 as a whole isn't difficult to nuzlocke. Oras is piss easy for example. It's just X&Y.
