nginx + php-fpm - where are my $_GET params?

You are not passing get arguments in your try_files call

in the question:

location / {
    try_files $uri $uri/ /index.php;
}

Should be:

location / {
    try_files $uri $uri/ /index.php?$query_string;
}

You can use either $query_string or $args, they are equivalent - except $query_string is readonly (or alternatively, $args can be updated by any other logic you may wish to add)


location / {
   try_files $uri $uri/ /index.php$is_args$args;
}