Change menu on login

If the user login try this code

<?php
if ( is_user_logged_in() ){
wp_nav_menu(array(‘menu’ => ‘loginmenu’));
}
else{
wp_nav_menu(array(‘menu’ => ‘publicmenu’));
}
?>

loginmenu and publicmenu is the slug of the menu.

Reference: https://codex.www.ads-software.com/Function_Reference/wp_nav_menu

You can also use a plugin.
There are a few out there, here is one of them:
https://www.ads-software.com/plugins/if-menu/