Install phpMyAdmin Ubuntu 16.04 and php7-fpm

Install phpMyAdmin Ubuntu 16.04 and php7-fpm

sudo apt update
sudo apt install phpmyadmin

This is a : no need to think setup for Ubuntu 16.04 with php7-fpm already installed.

Then copy paste just before the last } of the file the following block into /etc/nginx/sites-avaliable/default

location /phpmyadmin {
    root /usr/share/;
    index index.php index.html index.htm;
    location ~ ^/phpmyadmin/(.+\.php)$ {
        try_files $uri =404;
        fastcgi_pass unix:/var/run/php/php7.0-fpm.sock;
        include fastcgi_params;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;

    }
    location ~* ^/phpmyadmin/(.+\.(jpg|jpeg|gif|css|png|js|ico|html|xml|txt))$ {
        root /usr/share/;
    }
}

Save and restart nginx with :
sudo service nginx restart