As you know Nintex Workflow for Office 365 does not work with custom permission level (reference: Office 365 update item permissions action not allowed to add custom permission level ) so I would like to know if anyone has ever done pragmatically any workaround. Form validation would be something to look into as well.
Solved! Go to Solution.
You could use a REST method named ...roleassignments/addroleassignment with the action to call Web Services.
More info here >>>Set custom permissions on a list by using the REST interface