How to manage the Workflow History in Nintex for SharePoint Online, similar to SharePoint for On-Prem environments?

For O365 this is a setting that cannot be adjusted. For SharePoint (2010, 2013 and 2016) It is a farm setting in the timer services and it isn't accessible in SharePoint Online.

As a best practice, it is optimal to use Lists to store important workflow history for long term auditing and not rely on the workflow history lists for many reasons.

Available Options:
 

1. SharePoint Auditing: SharePoint has a builtin auditing capability. The good news is, the data collected survives migrations, upgrades and is permanent. On the other hand, the reports are not very end user friendly and turning on auditing in SharePoint (on-prem) can decrease performance by up to 15%. So be careful when going for this option. more information on SharePoint auditing can be found here.
2. List Data: You can leverage additional fields in SharePoint lists to store audit information as part of a list item or document. While this is great for an end user viewing the trail, it entails the same security concerns as using a SharePoint history list.
3. External Repositories: I’ve used this approach on multiple occasions with clients in highly regulated industries (mining for example). As part of the workflow, any information that is required was written into a database. That gives you a few advantages:
   1. No need to mess with the timer job. History and task lists stay lean and clean. All required information is hosted in a database.
   2. Reports can be pulled using Reporting Service, or other reporting tools without users having edit access to the actual data
   3. It functions as a secure store that no one can touch. Well, apart from the admin
   4. You have one single source of truth and regular database backups ensure that your auditing information is available all the time