I want to add a condition where workflow will determine if attachment is present or not on the list item so that it can move to different directions
I've never used Nintex for O365 before, but in the on premise version, there is always a reference to an item property called "Attachments". This is a bool variable which expresses if there are any attachments at all in the list item, meaning it will be true if there is an attachment and false if there are no attachments.
Do you have this item property as well?
Item property called "Attachments" is available in Nintex Workflow for Office 365 too
Retrieving data ...