Hi there - 

What is "TFS"? That'll be the first question I have.  

Team Foundation Server (TFS)

Here is a page of REST APIs for TFS: 

REST API Overview for Visual Studio Team Services and Team Foundation Server 

I believe you can utilize these with the Web Services action.

Here's a post about Web Services / Requests

Currently, there 's no integration among Nintex products and TFS ( or any other versioning repository )

I use TFS manually. I download all days ( while we are developing/designing ) and add those files ( exported from workflow/forms designer )

Depending on your Nintex License you can make exports in differente ways, for example >>>  

Hey ‌

From  your experience, are the REST APIs in the link I posted above useless when it comes to Nintex?

I'd like to know if my response wasn't helpful. 

I think that the API 'd be useful in the case you need to build a plugin for a specific tool.