Nav filter for wordpress

filter-nav.php

add_filter('wp_nav_menu_items','search_box_function', 10, 2);
function search_box_function( $nav, $args ) {
    if( $args->theme_location == 'main-nav' ) {
      //echo count($nav);
			//print_r($nav);

			//$navbit = explode("\n", $nav);

			//print_r($navbit);
    	if (!is_front_page()){
			$navHTML = "<li id='menu-header-home'><a href='". home_url() ."' title='Return to Home Page' alt='Return to Home Page' class='icon-home nav-icon'>&nbsp;</a></li>\r\n";
			}
			$navHTML .= $nav . "\r\n";
			if (is_front_page()) {
				$navHTML .= "<li id='menu-header-livechat'><a href='". home_url() ."' title='Click for LiveChat' alt='Return to Home Page' class='nav-icon icon-users'>&nbsp;Live Chat</a></li>\r\n";
			}
    return $navHTML;
		}

    return $nav;
}