if i add an attachement in nintex form , it should show tick-mark in right

As far as I can tell, looking into the attachment control, we cannot override its behavior and add additional images or checkmarks next to the attachments. The only way I can see is if you add custom JS into a classic nintex form that uses jquery to find the elements where the "delete" is showing. Target those elements in the HTML and add a checkmark to their left with jquery.