Use this as a starting point (included the stl) for your own nozzle.  Note that the longitudinal grooves are used to clip the tool to the holder and top partially locate the tool in the hose.  They need to be created to suite your application.  Given the flexibility of the hose they can be left off I think.

I would suggest PETG as the simplest material to print with as it gives some flexibility over PLA.  However I did print the test piece in PLA to check the fit.

I don't think it needs to be printed with a very fine layer size. I printed the test piece in 0.28mm DRAFT on a Prusa mk4s and I think it would be perfectly serviceable for use.