Small and easily printable nozzle box. Print the M6 inserts and glue into the box.
Use a 7mm socket tool/wrench to insert and remove the nozzles.

I used the Horizontal Expansion in Cura to (-0.2) when I printed the M6 inserts to get the threads loose enough so its easy to screw/unscrew the nozzles.

Used the same sliding lid design as https://www.youmagine.com/designs/container-with-sliding-lid

Update, added embossed Ultimaker logo on the box, and the Ultimaker Robot on the lid, downloadable as seperate stl's.