Nginx location directive doesn’t seem to be working. Am I missing something?

The problem here is that only the “best” location directive gets taken, in this order:

location =  <path>  (longest match wins)
location ^~ <path>  (longest match wins)
location ~  <path>  (first defined match wins)
location    <path>  (longest match wins)

Using this ruleset, your /phpmyadmin location directive is beaten out by the regular expression “.php$” location directive, so the former is ignored entirely. Additionally, your php fastcgi directive is hard-wired to your /home/me/dev directory, which means that phpMyAdmin is totally inaccessible. You can use a rewrite to get the correct root for your phpMyAdmin scripts:

location ~ \.php$ {
    set $php_root /home/me/dev;
    if ($request_uri ~* /phpmyadmin) {
        set $php_root /var/www/nginx-default/phpMyAdmin;
    }

    fastcgi_pass   127.0.0.1:9000;
    fastcgi_index  index.php;
    fastcgi_param  SCRIPT_FILENAME  $php_root$fastcgi_script_name;
    include /etc/nginx/fastcgi_params;
}