There's different kind of workloads, I use Docker containers the most, but jobs can also run on a system-level, there's also different types of operating modes, some jobs can be scheduled like cron, where other jobs just exposes a port and wants to be registered in Consuls service-mesh.

A job can also consist of multiple subtasks, an example could be nginx + django/rails subtasks that will be deployed together.

You can see an example of a Docker job here: https://www.nomadproject.io/docs/job-specification#example

With a few modifications you can easily allow for blue/green-deployments.