Nozzle wear means, that the material has a relatively rough and abrasive surface, which will work like sandpaper in the nozzle.
Continously printing with such materials will sand down the nozzle from the inside, this results in a larger nozzle diameter and the nozzle might also be sanded on the bottom. You can reduce this a little bit by lifting the printhead up two millimeters or similar during travel moves.
This affects brass nozzles, stainless steel nozzles are much more wear resistant and you can use them longer, before the diameter get’s unusably large.
These are all abrasive materials I know of:
-nearly all metal blends, especially stainless steel and iron composites
-carbon fibre blends
-to a certain extend even wood composites
I would advise you to get one stainless steel nozzle in a relatively large diameter, no less then 0,4mm.
Carbon fibres may clogg in smaller nozzles.
Proto Pasta sells some stainless steel nozzles, another great source for a variety of nozzles is e3d-online.com
Before buying a new nozzle, make sure, that it fits on your printer. Some printers need nozzles with female threads, some with male. Also the thread size (M5, M6, imperial) has to match with the new nozzle.
The downside of stainless steel nozzles is, that they are more expensive and don’t transfer heat to the filament as good as brass nozzles. You have to print slower with stainless steel nozzles and maybe increase the printing temperature a little bit.