For some guitars you can get a particular nut, depends on a brand, otherwise there are more or less standard ones, as well as templates (basically a block), that you service yourself - sand however you like, and cut string pits where they should be.

I would use super glue mixed with some sawdust, works great in a guitar world. But of course new nut is always better.

Marvelous, there's a lot going on there. Makes me think something like: "it used to be fun and exciting, now it's just that".