If can create custom fields to house any of the following data on an action in NXT:
- Mailchimp open dates
- Mailchimp link clicks
- Mailchimp Campaign ID (this allows you to update an action rather than create a duplicate if you add updated open and click data after the initial process)
- Mailchimp campaign name
Please note that these fields need to be created in the action attributes area of NXT in database view, you will need to set them all to be the 'text' type to house the data appropriately.