Signet seems to work fine on nostr:npub1cvqlzvmjercdn0ypsmv8f7j9lge6ahsnueh5rparh53wuswftv4q49yjt3 . There is an issue, however, where the default server signet.nunchuk.io:50002 is not intended for public use, so signet is only publicly useful if you manually change the network setting to a public server, like: ssl://mempool.space:60602

I found this issue report on github that indicates this default server will be changed to a public one in the next release... that was like 4 releases ago. 🤷

https://github.com/nunchuk-io/nunchuk-android/issues/74

Sorry if this is all old news... I just now ran into this issue myself and came across your thread... I thought it might be worth adding what I found so far.