After Nintex update/migration the "Nintex Workflow Maintenance Job" is missing from the farm.
Schedule a purge job using the Central Admin > Nintex Administration > Purge workflow data.
Once a purge request is queued, the job will be created automatically.
The job is not created or installed with installation of Nintex Workflow.
Nintex Workflow Maintenance Job, is only created when you run Purge Workflow Data under Nintex Administration in Central Admin.
See other more information and settings: