With a question that is less than 10 words, and could be searched through google in a mere 2 words, I do have to wonder if I should be nice and answer, or send you a link to a google search...
But today is a nice day, so I'll answer.
Firstly, you should probably take a look at: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/nav
Essentially, with many tags, the <nav> tag is more about organizing and grouping your source code in the best way possible that makes the most sense. For the most part it isn't majorly different from other tags, however there is a mention that:
User agents, such as screen readers targeting disabled users, can use this element to determine whether to omit the initial rendering of this content.