Interest on various topics comes in waves on HN. This week it's Zig, next week it's Scheme, the week after is Erlang, etc. Nothing out of the ordinary.
Programming languages in general go through hype waves here; back in the mid 2000s it was some combination of Lisp -> Ruby -> JS with bits of Erlang in and around those.
I think there's a small trend upwards for Zig & Nim right now. I've seen a few different front page posts for them in the last couple weeks. It at least convinced me to clone ziglings and get a feel for it this last weekend.
There's bursts of them and every 3-6 months I see one like this, more practical, and remember I don't need to read the others. Then I forget in 3 months. Rinse, lather, repeat. (to this 16 year veteran of HN, it reminds of early 2010s Haskell)
It may be due to the async/io changes which may have caused a wave of renewed interest in the language
Advent of code is coming, maybe lots of people looking for a language to learn with it?
still less than Rust posts.
What about more people using it? More than anything this looks to be natural evolution of language.