Tbh I would be using the meeting as an opportunity to get more information about nurture class and why they feel your son needs it.
It would also be an opportunity to say that you don't feel that your wishes have been taken into account.
However, as a parent of a teenager who is sensitive, and could have done with additional tools to help her navigate social situations, especially those in the school setting, I'd say give everything a go that the school will throw at helping him if they think he could do with a little extra support.
DD has always been a conscientious student, smart, well liked by her teachers, she's polite, she's friendly, helpful but she is quiet, and somewhat shy.
At home, we've worked on helping her find who she is, and have supported her to be her own person and embrace her individuality.
Her individuality has made her more likely to be picked on, there's nothing outlandish about her, but she is a bit different to the other teens in her year....
I wish that we had armed her with better resilience skills. It's hard to teach them when they are what we are trying to use to stop her feeling like rubbish.
Sorry, a bit of a tangent, but please keep an open mind, maybe it'll not be useful for your child, but it may well make a massive difference in 7/8/9 years time