Pour que phpMyAdmin soit accessible à l’adresse http://phpmyadmin.mondomaine.com

server {
        listen 80;
        server_name phpmyadmin.mondomaine.com;

        access_log /var/log/phpmyadmin.access_log;
        error_log /var/log/phpmyadmin.error_log;

        root /usr/share/phpmyadmin;
        index index.php;

        location ~* \.php$ {
                fastcgi_pass 127.0.0.1:9000;
                fastcgi_index index.php;
                fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
                include /etc/nginx/fastcgi_params;
        }
}

voir

https://desgeeksetdeslettres.com/programmation-java/securiser-lacces-a-phpmyadmin-avec-nginx-sous-ubuntu-server#phpMyAdmin