function my_login_redirect( $redirect_to, $request, $user ) {
    $redirect_to =  home_url($user->user_nicename);
    return $redirect_to;
}
add_filter( 'login_redirect', 'my_login_redirect', 10, 3 );

if ( is_user_logged_in() ) {
    $current_user = wp_get_current_user();
    echo '<a href="' . esc_url( home_url( $current_user->user_nicename ) ) . '">PROFILE</a>';
}