I imagine if you switch your Android phone into a Mass Storage Device mode, you can mount its storage as a USB drive in SXOS.
Maybe, I'm using kosmos tho. I never thought of trying honestly so I may play around. I imagine that there would have to be a port of goldtree or fluffy to Android get gold leaf or tinfoil on the switch to realize whats going on for usb install.
I also have a build of sxos rommenu t may read it as a USB and let me pick a nsp on my phone. This is all speculation, but now my curiosity is going, when I get the time I'll have to play around.