Forgive my ignorance, but is it possible to use an external looper pedal with the nano cortex?
I’m considering getting a nano cortex and would like to start using a looper pedal but I’m not sure if the lack of an effects loop on the nano cortex means that anything recorded on the looper will also be effected when changing presets.
I have seen the XSonic ULooper that works via USB but the website doesn’t list the nano cortex as a compatible device.
I have the nux loop core stereo and I just put it after the NC. It has a headphone out, too. So silent practicing is no problem.
Does that allow you to change the preset so you can have a clean rhythm part then play a lead tone over the top?
Sure, as the processed signal goes into the looper. First loop clean, than switch to solo and jam over it. It can store Jamtracks and you can even control it via midi, it has drums (basic, but do the job) and you can adjust the volume on the looper and on the NC. I‘m very happy with it and I help you any time, you have questions.
Thanks for the response, its been really helpful.
Would this be the same if a different looper pedal was used, like the Ditto looper or Boss RC-1?
All the same, but I love the stereo effects, so I chose a stereo looper and I would always choose a looper with a headphone out for placing silently with headphones. I have two children so silent playing in the evening is very important to me 
think about the signal chain, and how it gets changed. If you’re changing amp sounds (eg drive levels), if you do that after the looper, then anything that gets recorded on the looper will also be changed. So if you record a clean sound loop, then change to overdrive after the looper, your clean loop will get the drive and not be clean anymore.
General rule of thumb is looper is always last in the chain. And if you’re going into a multichannel amp, then you need to put it at the end in the effects loop. Since the Nano is all in one, just after the unit does the trick.