An easy way to prevent nonce reuse is to use a nonce big enough to be selected at random. 192 bits is big enough. XChacha20 provides that. I believe there ar

An easy way to prevent nonce reuse is to use a nonce big enough to be selected at random. 192 bits is big enough. XChacha20 provides that. I believe there are more general nonce extension constructions out there, but I don't know enough to recommend any. If for some reason you cannot (or don't want to) rely on your system's random number generator, consider using a hash of the chain as the nonce. Just make sure duplicated chains never happen, or revealing the existence and location of duplicates is not a problem. If you need to mitigate replay attacks… Err… I don't know.