Peter Mount on Nostr: no as it's still using 2 sets of keys, just that the sender uses a unique pair for ...

no as it's still using 2 sets of keys, just that the sender uses a unique pair for each message.

So it encrypts the message with it's private key & encrypts it's key with the receiver's public key.

The receiver then decodes the encoded key with the receiver's private key then the data with that key.

That said, it might be possible with a single key, but I need to refresh/re-read is that's possible.