I managed to solve this. For brand new users who aren't too familiar with web servers and backend (like me) it was fairly easy after some research. Hopefully this will save time for anyone in the future looking to do the same thing.
How to redirect subdomain to NodeBB IP w/ Nginx
This assumes that you have already added an A Record that points your subdomain to the NodeBB IP. This is fairly easy to use from your hosting provider.
There are many tutorials out there and they were helpful but, to me it felt there was plenty of information scattered all over.
This is what I did to get my subdomain to redirect to my NodeBB installation on DigitalOcean.
/* Update your package list to get the latest versions and Install Nginx*/ sudo apt-get update sudo apt-get install nginx /* Nginx is located in /etc/nginx by default */ cd /etc/nginx /* You want to go to your list of available sites here */ cd sites-available /* Create a copy of the default config and name it to your sites name */ cp default <your website name> /* Add configuration files for your website */ nano <your website name> /* Copy and paste config found here: https://docs.nodebb.org/en/latest/configuring/proxies/nginx.html into the server section of the code. NodeBB runs on port <your IP here>:4567 by default */ /* Enable it */ cd sites-enabled ln -s ../sites-available/<your website name> /* Restart nginx */ sudo service nginx restart
Go to your subdomain and make sure it works. Also be sure to change your config.json to your new url.
Hopefully this helps some beginners out there!