your client should present with a url to https://ditto.pub/oauth/authorize , paste your nsecbunker url there.
Discussion
🤔 im just regular nostr user (not a dev/dont have nsecbunker), i only login nostr webapps via nos2x extension, is there a way to login without nsecbunker?
Nope. You need an Nsec Bunker to use fediverse clients.
On Android, some apps like OxChat support the use of Amber
https://github.com/greenart7c3/Amber
Otherwise, exposing your nsec to the app directly is the only option.
was hoping theres an easier way so we can get mastod/fedi people switch to ditto/nostr