If you want to use Elastic Beanstalk's free tier with a single instance, you can use LetsEncrypt to get a free SSL certificate for your instances. Placing these files inside the appropriate directories will let you automatically install a certificate with every deploy.
Inside of your code, you should have the following structure:
.
├── index.js
├── package-lock.json
├── package.json
├── .ebextensions
│ ├── 00_install_certbot.config
│ └── 10_open_https_port.config
└── .platform
└── hooks
└── postdeploy
└── 00_get_certificate.sh
Credit to Marcos Escandell for the Amazon Linux 2 instructions that led me to here.
Do I need to reconfigure nginx to look at the new certificates or will these commands do it automatically?