No, mgiannopoulos[0], there is no limit on nesting replies that I'm aware of. I'm nesting another one now!
There is rate-limiting, though, which is probably what you hit. Wait a bit, and you can reply. Or click the "XX minutes ago", and I've found you can reply there.
Yeah, this is still at the top for me. Moving it along! I wonder how far it would have to go before it starts having problems. Or before apps start having problems. Doing this from my phone, and the comments are starting to get fairly difficult to read.
There is rate-limiting, though, which is probably what you hit. Wait a bit, and you can reply. Or click the "XX minutes ago", and I've found you can reply there.
[0] https://news.ycombinator.com/item?id=18186528