Yes there is a factory jig but need to make the clamp to go with it and then figure out how to use it.
Depending on the amount of damage to the blade factory specs won't always work.
I have countless hours developing my own equipment and the technique to sharpen Nils. That is only part of the battle, you have to know how to adjust the blade. Again, many hours involved studying the geometry of the Nils blade to know where the correction is needed to make adjustments. You have to demonstrate that ability to become authorized by Nils. There is only one other shop that authorized by Nils and not sure if they can adjust blades or if they're still in business and its not in MI. I enjoy what I do, keep my nose clean and don't care what "other shops" do. Good Luck...….
You can take a mildly dull blade and sharpen it with mixed success. Whatever you do "Don't touch the bottom of the blade" with anything, not even a little bit. That and pitting from rust will ruin a blade. I do have a process to resurface those blades have saved most of them.