In order to solve this problem I did the following:
Added one of the postgres drives (https://jdbc.postgresql.org/download.html)
to the nifi-1.11.4/lib/ folder I also added the file to a secondary folder within lib call /java11.
I safely shut down nifi and restarted my linux system.
I updated my DBCPConnectionPool to say the follow:
Database Connection URL jdbc:postgresql:///forestdb
Database Driver Class Name org.postgresql.Driver
Database Driver Location(s) No value set
Kerberos Credentials Service No value set
Database User admin
Max Wait Time 500 millis
Max Total Connections 8
Be sure you have your tables set up and all that good stuff.
Notice that I no longer included the path to the drivers locations. This should be due to Nifi loading the jar files into the system itself, by us adding it to the nifi-1.11.4/lib folder.
Adding the file to both the nifi-1.11.4/lib folder and the nifi-1.11.4/lib/java11 folder is probably not necessary but i was troubleshooting.
also note that I changed the Database Connection URL, no longer having localhost as part of the url.