That would be a matter of configuring plesk to accept updates via the nsupdate method. Using their API is going to be completely different unless it implements that somehow.
nsupdate is an implementation of a specific protocol, RFC2136.
This is a guide on what is required to get a bind server configured to accept updates:
https://www.netgate.com/docs/pfsense/dns/rfc2136-dynamic-dns.html
An alternate strategy might be to set up a bind server like in that link that serves as the master of a dynamic zone with the plesk as the slave but that would preclude managing the zone in plesk which is likely undesirable.
The heavy lifting for this probably needs to be done on the plesk. Instead of accepting updates via their proprietary API they should have a standard method such as RFC2136.