Current discussion and other activity is on the Nyancoins reddit: reddit.com/r/nyancoins/
This is by far the best place for any Nyancoin related enquires, and is likely to receive replies quickly.
Bitcointalk Forum (Thread started 5 October 2016). There are several older ones, but they contain incorrect out of date information.
Facebook page which was set up by the original developers, has not been used since 2014. However anyone can post to the page, so not entirely useless.
Updated 15 April 2018. Contact / impressum