Although MLCS is not directly supported in EazyBI, data can be imported using the advanced options provided.
To import and integrate Multi-Level Cascading Select custom fields in EazyBI is possible. You can follow the article made by the EazyBI team that explains how to import a Multi-Level Cascading Select field as an Account-specific calculated field
or a Global calculated field: https://docs.eazybi.com/eazybi/data-import/data-from-jira/javascript-calculated-custom-fields/calculated-field-examples/multi-level-cascading-field.