Well, it depends on various factors. If it manages to blend the elements of Naruto and the concept of Zanpakuto in an interesting way, it could be great. However, without actually reading it, it's hard to say for sure.
I'm not sure if it's a good fanfic just from the title. It might be amazing if the author has a creative vision. They could create unique storylines where Naruto characters interact with Zanpakuto powers. But it could also be a mess if not done properly. Maybe it combines Naruto's ninja skills with the power - up mechanics related to Zanpakuto. Or perhaps it just has some characters using Zanpakuto in the Naruto universe in a really cool way. But again, this is all speculation without reading it.
It's difficult to determine if 'naruto strongest zanpakuto fanfic' is a good one. Firstly, the idea of mixing Naruto and Zanpakuto is quite interesting. If the fanfic has well - developed characters that are both true to their Naruto selves and also able to handle the Zanpakuto powers in a believable way, it could be a hit. For example, if Naruto himself gets a Zanpakuto and has to learn to master it while still using his own ninja abilities like the Rasengan and Shadow Clone Jutsu. Also, the plot could be exciting if it involves battles against powerful foes with the added element of Zanpakuto. However, there are also risks. The two concepts come from different universes and if not integrated smoothly, it could lead to a confusing and unenjoyable read.