We guess you are talking about getalby.com web account - where you can get your @getalby.com LN address and a wallet.

But for Nostr log-ins and use, you should use the Alby Browser Extension (for Chrome, Brave, Firefox). You paste your nsec there.

The Browser Extension can be connected to the Alby Account or other lightning wallet, it doesn't require log-ins.

Let us know if you need more guidance 😉