do you not have the nintex forms customize forms button in the ribbon (library tab) on your library?

Hi Cassy. I do have the button, but it is greyed out.

When I look at the items in my library, I can see they still have the purple InfoPath icon. So I am assuming I need to delete the template somewhere. In a list I was able to do this by changing the default form back to SharePoint form, then deleting the InfoPath template. I am not sure if there is something similar to this in a Library.

What permissions do you have to the library?

Alternatively, you can access Nintex Form using below link:

http://siteurl/_layouts/15/NintexForms/ListFormDesigner.aspx?List={ListGUID}  

ListGUID can be obtained by editing the list settings and copying it from the address bar.

Hi there

Thanks for the replies. This is not a list, it is a Document Library. What I didn't mention as well, is that it is a Form Library. So it is a Library, with the default document type set to Infopath.

‌ I have full control permissions on this form library

Hi Kirk,

unfortunately with Nintex Forms you cannot have a "form library" with forms that opens with Nintex Forms..

You can customize also a Document Library, so when you upload a document, the form that shows document properties is made with Nintex Forms, but you cannot do with a Form Library (the properties form is the form itself, and it's currently not supported)

My suggestion is: could you change the scenario and use a list instead of a form library? In this way, each list item will open showing the Nintex Forms

To elaborate further on this, an Infopath form library contains actual files, rather like Word documents or Excel spreadsheets.

Therefore, it would be impossible to replace these forms (files) with a Nintex form as a Nintex form does not create an individual file.

As ‌ suggests the closest equivalent of what you're looking for is a list with a Nintex form. But remember, you are not creating a file with your Nintex form, you are creating an interface to populate data into rows. The same applies to a Document library as you are providing an interface for the user to populate metadata into a row that also contains a document.

Thanks everyone your comments. I think this answers my question now.