This kind of conversation has happened to me a few times at various tech meetups.
Great to meet you! So what kind of things do you work on?
Oh, I can't tell you.
Where can you go from here? The weather? Sports?
At meetups like this, the work is what binds us together. I understand that you can't talk about your work if your employers impose an NDA, but that doesn't have to mean the end of the conversation. How about a side project? Have you started one of those? It may only take a few hours on a weekend to get something running, and then you have something you can freely use to better connect with people. If not a side project, maybe there are a few libraries or tools you've been using that are interesting to you. Maybe you could talk about them.
Participating in a tech meetup may initially be about hearing the presentations, but it doesn't end there. You'll want to give something back too. This means having something to talk about with your peers. Your NDA doesn't have to stop that.