Filtered means that a firewall, filter, or other network obstacle is blocking the port so that Nmap cannot tell whether it is open or closed
https://nmap.org/book/man.html
We'd like to provide suggestions for resolution, but the issue at hand is not Nagios related. It is a network problem and I would start with AWS.
As previously mentioned, let us know if you encounter problems after you've confirmed Nagios XI and the client can establish a tcp connection.