nestedpages_add_links_to_cpt.php

<?php
/**
* Add the link post type to the query args passed to the listing query
*/
add_filter('nestedpages_page_listing', 'nestedpages_add_links_to_listing', 10, 2);
function nestedpages_add_links_to_listing($query_args, $post_type)
{
	if ( $post_type->name == 'custom-post-type' ) $query_args['post_type'][] = 'np-redirect';
	return $query_args;
}

/**
* Add the link interface to the custom post type
*/
add_filter('nestedpages_show_links', 'nestedpages_add_links_interface', 10, 4);
function nestedpages_add_links_interface($show_links, $post_type, $user, $listing)
{
	$show_links = ( $user->canPublish($post_type->name) 
		&& ( $post_type->name == 'page' || $post_type->name == 'custom-post-type' ) // Custom post type added here
		&& !$listing->isSearch() 
		&& !$listing->isOrdered($post_type->name) 
		&& !$listing->settings->menusDisabled() 
		&& !$listing->integrations->plugins->wpml->installed ) 
	? true : false;
	return $show_links;
}