Looking for a menu building plugin

Hello,

I am wondering if there is a menu building plugin out there. I have just over 500 categories for my shop that I need to put into my wordpress mega menu, but adding each one individually would be extremely time consuming. I’ve been searching for the entire day and can’t seem to find a plugin that can upload a csv that will update the menu with all my categories and sub categories.

It doesn’t have to be an upload/import plugin, just need a faster way to put all my categories into the menu. Not looking for a plugin that will replace my menu since I’m using my themes menu.

My theme: http://yithemes.com/live/?theme=nielsen

Thanks!