// Filter wp_nav_menu() to add profile link
add_filter( 'wp_nav_menu_items', 'my_nav_menu_profile_link' );
function my_nav_menu_profile_link($menu) {
global $bp;
$username = $bp->loggedin_user->userdata->display_name; // or 'user_nicename','user_login' 	
	if (!is_user_logged_in())
		return $menu;
	else
		$profilelink = '<li><a href="' . bp_loggedin_user_domain( '/' ) . '">' .  $username . '</a></li>';
		$menu = $menu . $profilelink;
		return $menu;
}