I have created a workflow that will automatically create a site for approved requests with a unique URL. Though now I need to take information from the original request and migrate it to a list that is used in the template for the created site. Is this possible with Nintex WF? and if so? What are some recommendations to do this?
Depending on what information you are planning on migrating into the newly created list, you should be able to do so with some web service calls. You can always call the UpdateListItems service and loop through all the items you want to add.
There are some example out in the community if you search for what you are trying to do.
I would recommend checking out Create List item using Web Request as it points to some "how to". I have done this and detailed my steps in my blog about but again, not sure the type of information you are pushing through or what format it is in already.
If you are copying items from one list to another, it should be straightforward, but if it is in a file or within the form, it may be a bit more troublesome to get it out and in the right format.
Hope this helps!