software

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It depends on who is doing it If you have not done it before, I wouldn't suggest trying it yourself on this guitar. But as long as you have 1) the old nut 2) the proper tools (glue, files/cutting, etc) and 3) patience, it's not too hard at all.

Any decent tech can replace it very easily if you have the old nut, it might even be better since they will be starting from scratch and can make sure everything is aligned, spaced, and cut properly.

MJ

and if i dont have the old nut?

If the person you're taking it to is competent not hard at all.
The sizing is pretty straight ahead,so is the shaping.
As for the slots,using a straightedge between the saddle and the tuning key,(if the person doesn't have a template guide),will give you the result.You can also use the wear marks on the frets as a guide.
An experienced shop would see broken nuts and snapped 'stocks enough to be able to work with the neck.
If the shop you go to says it's going to be harder without the original nut-wish them a nice day and leave!!!!!