upstream filehoster {
    # the hostname/ip and port on which the sharex_server script is reachable
    server file_hoster:80;
}

server {
    listen 443 ssl;
    listen [::]:443 ssl;
    http2 on;

    ssl_certificate /path/to/fullchain.pem;
    ssl_certificate_key /path/to/privkey.pem;

    server_name your-domain.net;

    # Include the location in your ShareX_Storage base_url
    location /f/ {
        # Should match ShareX_Storage max_filesize
        client_max_body_size 100M;
        proxy_pass http://filehoster;
    }
}