What you will need to do when you renew your TN visa at the border is to present a new offer letter with the Developer title with developer responsibilities. What the TN reviewer is looking for is to make sure your responsibilities matches your University/College degree. As long as your degree matches your new position, you'll get approved. In your case, it's not much of a stretch.
You'll probably get denied if you have a CS degree and now you are nurse working in a Hospital.
Sources: I worked in the US with a TN visa from 2006 - 2010 until I got my green card and no longer needed it.