lol that sounds like something my mom would do. And in my case, I just interpret it as her being stupid and petty and mentally tell her to go screw herself.
But anyway, you should try talking or writing her a letter. In this case, you can be pretty clear: 'I repeatedly asked these people to be quiet and they wouldn't.' Reenforce your problems sleeping. You can even go far as to say that you feel hurt that she, of all people, would ALSO choose to disrespect you and what you need. Tell her you need her for support. Whatever, be as truthful as possible.
If this is an ongoing problem, maybe you should talk to someone higher up at the clinic. You can tell them that you repeatedly ask the nurses to be quiet and they refuse. Getting someone higher up to tell them to keep it shut may do the trick.
I would've explained to her that the behavior of the people who are supposed to be medical professionals was a lot more shameful. That you've told them several times before that you have trouble even getting a little sleep, so if you finally, do that they should let you have it, yet they've ignored it each time. Then I'd ask her how reasonable she'd be after not having had a proper night's sleep for as long as you. Not to mention having the stress of being in the hospital and waiting for a transplant on top of that. It's not like it's just a regular strip of insomnia of an otherwise healthy person. Once you are eligible for that transplant I imagine she'd want you to be as well rested as you can be for it and have your strength up too.
Maybe if you explain the reality of the situation to her in that way, it might sink in better.
You know, I suggest you write your mother a letter.
Calmly choose your words. Don't blame too hard, but very clearly explain why it is so important to you, and how bad is it when you don't get your sleep. Tell her how disrespected you feel, when no-one respects your needs. How alone you feel, when she doesn't protect you against the unprofessional behaviour of that nurse.
If you have a doctor overseeing your treatment, try to talk to him/her about the nurse's behaviour. Explain why it's a problem for you. Explain that it stresses you. Ask that your very reasonable need be met. Do not compromise about being around left/right ear. It is easier to make a complete ban on non-related talk around you. There is no reason, why there should be off-topic chatter, when it bothers you that much. nurses have breaks, they can gossip then.
If you give your mum a letter, and she really doesn't help you, you have no other choice than to take it up with the medical director. Maybe he/she can control the nurses and possibly even explain to your mum why you are right.