Personally I don't mind psionics in the setting but I've seen it done badly.  I'd rather keep the nanobots out, mostly because you're a prisoner and fancy gadgets will have been taken off you... but again it depends a bit on what you want to do with them, which I appreciate is a super-vague answer!

What exactly are you thinking of?  I'm keen to keep things reasonably grounded and to avoid anything that will cause 'power creep' in the cast.