Enable HTTP:
nexus.h2.httpListenerEnabled=true nexus.h2.httpListenerPort=8099
If docker is used don't forget to expose ports 8099:8099
H2 http accepts only connection to localhost, so use ssh TCP forwarder:
ssh docker-nexus -L8099:localhost:8099
Open http://localhost:8099 and connect to JDBC URL: jdbc:h2:file:nexus with empty credentials.