/etc/nginx/sites-available/pi.hole

nginx.conf

server {
        listen 80;
        listen [::]:80;

        server_name pi.hole;

        allow 192.0.2.15;
        deny all;

        root /var/www/html;

        # Add index.php to the list if you are using PHP
        index index.php index.html;

        location / {
                # First attempt to serve request as file, then
                # as directory, then fall back to displaying a 404.
                try_files $uri $uri/ =404;
        }

        location ~ \.php$ {
                include snippets/fastcgi-php.conf;
                fastcgi_pass unix:/var/run/php/php7.0-fpm.sock;
        }
}

Used on Raspbian GNU/Linux 9.6 (stretch)