Removing a Parent Theme’s Menu Items

Of course right after I post this, I find an answer…so hopefully someone else can benefit from this. For me, the answer was instead of unregistering nav menu items, I needed to just remove the action…so my function now looks like this:

function remove_cornerstone_menus() {
    remove_action('init', 'cornerstone_menus');
}

add_action('init', 'remove_cornerstone_menus');

Worked like a charm.