Proof that either Zoro or Nusjuro used Advanced Conquerors? Looked like basic Armament to me, especially since their weapons touched.
Nusjuro didn't use his ice powers in the clash. In fact, he didn't use them on anyone other than the Pacifistas.
Nusjuro didn't meet Zoro's Rashomon with an attack of his own, but rather a basic block, yet that alone was enough to match Zoro's attack power, which was one of the most impressive feats on Egghead imo.
The points above makes it absolutely clear that Nusjuro was not in fact using his full power.
Nusjuro didn't use his ice powers in the clash. In fact, he didn't use them on anyone other than the Pacifistas.
Nusjuro didn't meet Zoro's Rashomon with an attack of his own, but rather a basic block, yet that alone was enough to match Zoro's attack power, which was one of the most impressive feats on Egghead imo.
The points above makes it absolutely clear that Nusjuro was not in fact using his full power.