Some people have discussed the issue of Chris having a public defender and how he might not qualify for one. He could still try legal aid (does UVA have a law school? Usually law students will take cases to gain experience) or try and get a lawyer to do it pro bono work for them. My understanding is most state bars suggest that practicing attorneys do a certain number of pro bono work, but I'm not sure if a mentally deficient manchild macing a store clerk for asking him to stop defacing a sign for a video game would be done pro bono. I get that technically Chris owns a house and a car, but he's also receiving government aid and I pretty sure on top of the "tugboat" he gets food stamps and Medicare.
Someone else has probably said this but the US does do things differently than in the UK, though we do have the same common law tradition. Again, this is from my INTERNET LAWYER experience but it's extremely difficult to pull off an insanity plea and there's a high criteria that needs to be met. I don't think Chris spazzing out over a Sonic Boom would meet that criteria. I've heard some jurisdictions have a verdict of "guilty but mentally ill" where you're still found guilty but the fact you're mentally ill is taken into account and you're sent to a psych hospital.
I've mentioned this before but I think he got the whole "sensory overload" idea from that Temple Grandin talk he went to. It's sad that she probably talked about how she faced a lot of adversity due to her autism but she managed to use her autism to become a brilliant academic in her field, when all Chris seemed to get from it was "sensory overload" is a thing and he seems to think it's an excuse for vandalizing private property. I know quite a few people on the autism spectrum and for them, sensory overload just means that they're being overwhelmed and might need to go somewhere quiet for a bit or do something soothing. Chris seems to think that suffering from sensory overload means going into a rage and going apeshit on people.
Someone else mentioned that he's going to try and claim discrimination on the basis of being transgendered. I had a feeling that when he was asking people from HRC for help, he was playing the transgendered thing to get their help. Obviously I don't see this playing out at all in court but I could see Chris expecting that because he's transgendered, that means if someone does something mean to him, it's automatically discrimination.