I don’t remember much about the specifics of OCB. But the xchacha/xsalsa20 approach is completely generic, so can be applied to any cipher: effectively just run

I don’t remember much about the specifics of OCB. But the xchacha/xsalsa20 approach is completely generic, so can be applied to any cipher: effectively just run a large nonce through a PRF to derive a fresh key for each message.