I'm currently playing a bit with PyNaCl (python binding to libsodium) and I want to use the secretbox for symmetric encryption between two parties, which means they both must know the (in my case randomly generated) nonce, so I would just send it with the ciphertext. I derive the secret key with argon2id from a password, but this needs a salt. So I was wondering whether it would be dangerous to use parts of the nonce as the salt, so I only have to transmit the nonce. I don't think it would be problematic because the salt is just used to prevent rainbow table attacks etc. I know it is dangerous to reuse a (key,nonce)-pair, but since the key is derived from both a password and the salt and the nonce is randomly generated every time, I don't see this as a problem.
Am I correct or is there a problem I'm not thinking about? Or is there a better approach? Also I'm asking more from the academic side of things and less from my implementation, that was just to explain how I came to the question.
In case there is already a similar question, please point me towards it, I did try the search but nothing really fitting came up.
Tl;dr: Is it generally cryptographically problematic to use a part of nonce for an AEAD scheme as a salt for a KDF ?