You configured Nginx on a Linux server. You want to see if there has been activity on the website (e.g., via a web browser). What log file, visible on the back-end, has records of web browsing activity?
It is often here: /var/log/nginx/access.log
For general Nginx purposes, the nginx.conf file specifies the location of the Nginx logs and the names of the log files themselves. To find this file, run this command:
sudo find / -name nginx.conf
View it and look for "access_log". This stanza should have what you are looking for (if the access.log file is somewhere other than the default location). For Apache web server logs, see this posting.