Adapted from https://rtcamp.com/wordpress-nginx/tutorials/multisite/subdirectories/minimal/

Nginx WordPress Multisite Subfolder config

server {
        ##DM - uncomment following line for domain mapping	
        #listen 80 default_server;
        server_name example.com *.example.com ;
        ##DM - uncomment following line for domain mapping
	#server_name_in_redirect off;

	access_log   /var/log/nginx/example.com.access.log;
	error_log    /var/log/nginx/example.com.error.log;

	root /var/www/html/example.com;
	index index.php;

	if (!-e $request_filename) {
		rewrite /wp-admin$ $scheme://$host$uri/ permanent;	
		rewrite ^(/[^/]+)?(/wp-.*) $2 last;                     
		rewrite ^(/[^/]+)?(/.*\.php) $2 last;                   
	}

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

	location ~ \.php$ {
        try_files $uri =404;
        fastcgi_split_path_info ^(.+\.php)(/.+)$;
        #NOTE: You should have "cgi.fix_pathinfo = 0;" in php.ini
 
        include /etc/nginx/fastcgi_params;
		fastcgi_pass unix:/tmp/php-fpm.sock;
        fastcgi_index index.php;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
	}

	location ~* ^.+\.(ogg|ogv|svg|svgz|eot|otf|woff|mp4|ttf|rss|atom|jpg|jpeg|gif|png|ico|zip|tgz|gz|rar|bz2|doc|xls|exe|ppt|tar|mid|midi|wav|bmp|rtf)$ {
		access_log off;	log_not_found off; expires max;
	}

	location ~ /\. { deny  all; access_log off; log_not_found off; }
	
	# This should match upload_max_filesize in php.ini
        client_max_body_size 20M;
}