In Jira Server and Data Centre, Jira administrator can hide the eazyBI link from the top navigation menu.
Go to Jira Administration → Manage apps and find "eazyBI Reports and Charts for Jira" app. Expand all modules of the app.
Find the eazyBI home link module and Disable it to hide the top navigation bar link.
Note the users can still access eazyBI if they know the application link
JIRA_BASE_URL/plugins/servlet/eazybi or access eazyBI app throu published eazyBI reports on Jira dashboards.