I got it! You're answer was a big part of it. For those who might follow in my footsteps, I'll try and list the instructions as best I can.

Setup NGINX proxy manger to use SSL then add the following code in the "Advanced Section" of the hostname:

proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Host $host;
proxy_set_header X-Real-IP $remote_addr;

Open ossn.config.site.php (Located for Me: /var/www/html/configurations) and make the following edits.

Add the following code before $Ossn-> url

 if (isset($_SERVER['HTTP_X_FORWARDED_PROTO']) && $_SERVER['HTTP_X_FORWARDED_PROTO'] === 'https') {
    $_SERVER['HTTPS'] = 'on';
}

change the $Ossn->url = "https://yourdomain.com/"

Pictured Example

Clear browser cache (May not be needed) and all should be working.

From your website it appeared to be css working fine you need to edit

configurations/ossn.config.site.php and change it to https from http (site url) note that site url must be static

$Ossn->url = "https://social.builtforgeeks.com/";

Not

$Ossn->url = "http://{$_SERVER['SERVER_NAME']}/";

Correct me if I am wrong, but I believe that is for running the OSSN on NGINX rather than Apache. I am fine leaving the web server running on Apache (I just used the .OVA file from the OSSN download page). I just want to put it behind a reverse proxy, which in this case is "NGINX Proxy Manager"

Simply use https://github.com/opensource-socialnetwork/nginx