I have read far too much brainrot catgirl manga that I probably take it for granted everyone knows what nyaa/nyan means. Fun fact, "wan" is woof!
The cat's name is Gomanosuke (胡麻の助), and I think you're right about the origin. :) The full page shows them calling him this in context.
Source: We Want To Talk About Kaguya - chapter 182, page 4
Source: Mato Seihei no Slave - chapter 3, page 15.
Source: Please Don't Bully Me, Nagatoro - chapter 112, page 7
Sauce is Dark Summoner to Dekiteiru. (smut warning)
I have read far too much brainrot catgirl manga that I probably take it for granted everyone knows what nyaa/nyan means. Fun fact, "wan" is woof!