Hide menu in one page

You can do something like this.

Find the id of the page from the admin panel(when you edit the page, id is available in url )

For example page : portfolio(id 1631)

.page-id-1631 #nav-section{
   display:none;
}

Hi,

here is a plugin that may be of help.

https://www.ads-software.com/plugins/page-specific-menu-items/