Indeed you can - although if it has an error it will halt and need a reset as that was a bug that could not be removed in time for the Jam! I will continue to develop this and find the bug.
The latest version of NextZXOS also has improved 48K ROM support and I have been experimenting with using the main Menu 48K Cart option (now under Interface 2) - then you just need one pair of OUT's to disable onboard SD to use the microdrive. There is no way back to NextZXOS though but, things are getting simpler...