Yes you can. You'll just need to create a single-server cluster. Once you're done, you can deploy as many apps as you want to it.
You'll need to add domains to each app so that NGINX knows which app to serve when a request comes in. If you don't add domains, NGINX will just serve up the first app it finds for every request.
Just keep in mind that the RAM of your server will probably be the limiting factor of how many apps you can run.
When you create a multi-server cluster, you choose how many servers you want and what size each of them should be. Then, you can tag each server with the roles it should have.
For example, you can tag one server as your load balancer, another server as a web server and the cron server, and then one server for your databases and background workers.
You can add a new server to the cluster at any time and move roles around as needed. We don't let you migrate your database servers to prevent downtime from migrating data.