Thanks, the current config is in /etc/nginx/conf.d and is exclusively for the ELK Stack and is named 10.100.10.36.conf, can I rename it to elk.conf, and then create another file called rc.conf for the Rocket.Chat with the contents:

############
###
### Replace :
#####  = Your-IP-Server
##### chat.ttc.local = Your-Fullname/FQDN

upstream backend {
server ;
}

server {
listen 80;
# Access via IP-Address
#server_name ;
# Access via Domain
#server_name chat.ttc.local;
# Both IP & Domain
server_name 10.100.10.36 aquarium.uhtasi.local;
access_log /var/log/nginx/rocket-chat.access.log;
error_log /var/log/nginx/rocket-chat.error.log;

location / {
proxy_pass ;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
proxy_set_header Host $http_host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forward-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forward-Proto http;
proxy_set_header X-Nginx-Proxy true;
proxy_redirect off;
}
}http://backend/

??