Author Nickname URL Friendly

Using the below code to chnage the author page url to use the “nickname”. Works ok but when the nickname is more than one word it doesnt make it url friendly. Any way to do this?

add_filter( 'request', 'wpse5742_request' );
function wpse5742_request( $query_vars ) {
  if ( array_key_exists( 'author_name', $query_vars ) ) {
    global $wpdb;
    $author_id = $wpdb->get_var( $wpdb->prepare( "SELECT user_id FROM {$wpdb->usermeta}    WHERE meta_key='nickname' AND meta_value = %s", $query_vars['author_name'] ) );
    if ( $author_id ) {
        $query_vars['author'] = $author_id;
        unset( $query_vars['author_name'] );    
    }
  } 
  return $query_vars; 
}

add_filter( 'author_link', 'wpse5742_author_link', 10, 3 );
function wpse5742_author_link( $link, $author_id, $author_nicename )  {
  $author_nickname = get_user_meta( $author_id, 'nickname', true );
  if ( $author_nickname ) {
    $link = str_replace( $author_nicename, $author_nickname, $link );
  }
  return $link; 
}

add_action( 'user_profile_update_errors', 'wpse5742_set_user_nicename_to_nickname', 10, 3 );
function wpse5742_set_user_nicename_to_nickname( &$errors, $update, &$user ){
  if ( ! empty( $user->nickname ) ) {
    $user->user_nicename = sanitize_title( $user->nickname, $user->display_name );
  }
}