How to enable access to nodejs on different port, with ssl now installed

For a number of years I have had my website at another host, accessing a ‘visual rule editor’ using nodejs on a digital ocean Ubuntu 16.04 droplet (listening on port 1880) - inside a wordpress html frame, I have decided to do two things:

• port the website to digital ocean
• add ssl - using letsencrypt - for sandbox.ritc.io

I now have the wordpress site running, and accessible using https.

The html frame used to be accessed like this (second line): <?php Starkers_Utilities::get_template_parts( array( ‘parts/shared/html-header’, ‘parts/shared/header’ ) ); ?> <iframe src=“http://sandbox.ritc.io:1880/?env=website#” width=“100%” height=“600”></iframe> <?php Starkers_Utilities::get_template_parts( array( ‘parts/shared/footer’,‘parts/shared/html-footer’ ) ); ?>

I am expecting to be able to change it to something like: <?php Starkers_Utilities::get_template_parts( array( ‘parts/shared/html-header’, ‘parts/shared/header’ ) ); ?> <iframe src=“https://localhost:1880/?env=website#” width=“100%” height=“600”></iframe> <?php Starkers_Utilities::get_template_parts( array( ‘parts/shared/footer’,‘parts/shared/html-footer’ ) ); ?>

What reference should I use and how do I configure nginx to proxy to nodejs, which is listening on port 1880?

Thanks

Colin Goldberg