Many files across the Nexus sites depend on other files, official expansions or official DLCs in order for them to work properly. Up until this point the only way for people to find what files a specific mod needs has been to look for the information in the author's file description or in the ReadMe file. Some files have many, many file dependencies and finding all the mods can become a bit of a chore for all involved.
The latest feature addition for file authors is a new option in your "Manage files" section for all your files called "Required files". Using this page will enable you to select which official expansions and DLCs your file requires in order to work properly. Similarly it will allow you to find and select files on the Nexus sites that your file needs or provide external links to files not available on the Nexus sites for users to download.
It's all sexed up with some efficient AJAX/jQuery coding (so you'll have to allow the scripts in your script blockers if you use them) so all your additions won't have to wait for the page to reload. Finding mods on the Nexus should be much easier with an auto-fill input box that will find the most relevant files based on what you put in to the box.
Once you've added your requirements a new tab will be added to your file page called "Requirements" that will list all the requirements and provide links to the file pages so your users can head off and download all the necessary files. Similarly there is a new entry under the "Options" box that provides the number of files that require your file in order to work (with a link to a page that lists all the files that have a dependency on your file).
My current focus is on reducing the amount of clutter mod authors need to put in to their mod descriptions in order to get all the necessary information out there. Mod descriptions should really be for, guess what, describing the mod! Unfortunately lots of authors have lots of information they need to get out there and the actual mod description, i.e. what the mod actually does (!!), can get lost in-between change logs, news, troubleshooting, etc.. Hopefully this new feature should help to reduce this clutter.
As always this addition requires some work on the part of the mod authors in order to work properly and if there are any problems then leave a comment on this article and I shall explore it.