Eh to henerate a decent nozzle takes some precision lazer drilling (e.g.trumpf) or edm drilling (e.g posalux)and some grinding + a quality test bench. Its not that easy having good lowtech solutions either.

Yeah you're definitely gonna want to purchase nozzles. They're extremely precise and manufactured to very high tolerances. I've rebuilt plenty of 30+yr old injectors and haven't yet been unable to find newly manufactured or new old stock nozzles though.

EDIT: I did have some nozzles bored out a little bit once by a shop with EDM equipment. Terrible results, not worth it.