Thanks for the screens, they helped me understand exactly what you want to do.
To pull this off you will have to do what I noted earlier:
1) Obtain the XML by storing it into a list column (I think this makes it easier than dealing with Form Data directly).
2) Query the XML inside of your workflow by using XPath to store the results into collection variables.
3) Loop through the collection variables and apply HTML formatting.
4) Update the column in your list to display the html results.
If you are brand new to Nintex or XML/Xpath concepts, looping, etc.. then it will probably take a bit to wrap your head around what I'm describing here, as these are more advanced topics as compared to some of the out of the box features of the product.
Here is a great post that contains links to all the concepts that you will need to understand and in more detail than I described above:
Formatting Results to an Email
Thanks,
Mike