Lookml file to chronicle

No, Google SecOps uses embedded Looker and creating or customizing your own LookML is not supported.

There is a new native Dashboard capability in Chronicle SIEM and that does include full API CRUD support, as well as an import and export capability.  If you don't have access on the preview, I would recommend requesting it via your Account Team or Partner.

Please see - https://www.googlecloudcommunity.com/gc/Community-Blog/New-to-Google-SecOps-An-Introduction-to-Native-Dashboards/ba-p/856924- for more info