How to use the wpsnonce clone post link?

One option is to use wp_add_inline_script() to inline the action url to the page source. This can be done for example on the admin_enqueue_scripts action.

In the example below I used admin_url() with wp_nonce_url() to retrieve the nonce wp-admin url and then added the query paramters to it with add_query_arg().

add_action( 'admin_enqueue_scripts', 'my_admin_action_url', 5 );
function my_admin_action_url() {
    $actionUrl = add_query_arg([
        'action' => 'duplicate_post_clone',
        'post' => 30808,
    ], wp_nonce_url( admin_url('admin.php'), 'action' ));

   wp_add_inline_script( 'jquery', "var myAdminActionUrl="{$actionUrl}";" );
}

The url should be now available in your script via the myAdminActionUrl variable.