[dropzon3]

You'd need an OS that can run on the architecture. Not just any old USB bootable OS can be used. You also need the access to partition and wipe the drive(usually means rooted)

So if you're talking about the iPod touch gen4 then it runs with an ARM processor and there is an ARM version of kali. SO in theory yes you can install Kali onto your iPod. You'll need to replace your bootloader also (quick google says there is iBoot for that but I'm not sure if that is completed) so that you can boot another OS.

That is the first step being able to boot another OS then you need to install it onto the drive which is another problem for the iPod. I highly doubt you can run an interactive installer so you're going to need to install it manually. Of course all this is just 'in theory' in practice I'm going to say no you probably cannot.