There is no email required. There is no registration. You only need the private key and public key pair that was generated when you created your profile on whichever app that you're using. Keep this private key, sometimes called a secret key, safe. It unlocks your identity on Nostr applications.
P.S. call me dumb, but what is coracle and what is Nostr? Is Nostr part of the wider platform Coracle??
Nostr is protocol, like email. Coracle is an application or platform that is built using the Nostr protocol. Nostr is a wide ecosystem of applications. Visit nostrapps.com to see more examples of what's available and being built with the Nostr protocol.
Gotcha. Thank you for explaining in simple terms!