If you encounter a “No input file specified error” when you try to access your phpMyAdmin alias on your Nginx web server, please try to add this line to your vhost or default configuration:

location ~ \.php$ {
    fastcgi_param   SCRIPT_FILENAME $document_root$fastcgi_script_name;

This fastcgi_param line was missing into my configuration to make it work. If you had the same problem and found another workaround please let me know in the comments section below :)