@Jake could you assist here please?

Hi @EdwardSMaTeresa 

Workflow tasks are located in the Workflow Tasks list on the SharePoint your workflow list is located on.

Any task assignees will require access to said list to be able to review and complete tasks and would require minimum contribute level access.

An option for you to be able to maintain security would be to configure the workflow to have its own Task List, this can be done in the workflow settings by selecting 'Task List' here you can select an alternate or create a new task list.

Once a new task list is created then you can permission that list independently to allow external users to approve.

To do this, first start by going to the task list settings and select Permissions for this list once there, select Stop Inheriting Permissions.

Then using the Grant Permissions action

adding 'everyone' to contribute permissions by simply typing Everyone.

Select the Show Options and ensure to select permission level to Contribute

And please ensure that 'Send an email invitation' is unchecked. this is important as to not send an email to everyone in the company. 

This will make it so everyone can access this list to action tasks but no other lists in your site.

Please also keep in mind if you use lookup fields on the task forms, permissions will be required for those lists also for any task assignees.

I must also stress that the above advise is based on the assumption you are using a standard SharePoint configuration and you have the authority and access to make these changes, That may not be the case so if you have issues with the above steps please contact your Sharepoint administrators.

Nintex only utilises the SharePoint infrastructure in this case and we must abide by the same permissions afforded by the SharePoint.

I hope this assists you.

Kind regards

Jake