How should I identify the inline javascript that is the dependent of a wp_enqueue_script?

Try this…

function load_new_js() {
    if( is_page( 692 ) ) {
        wp_enqueue_script(
            'modify_plugin_js',
            get_stylesheet_directory_uri() . '/mycustomscript.js',
            array('jquery','greetingnow')
        );

    }
}

If that doesn’t work, what plugin are you using?