Some nested queries

Hi.
I need to get cpu metrics from (and grouped by) nodes that are returned by another one query.
I was thinking about something like this:

SELECT "usage_idle" ROM "autogen"."cpu" where host in (SHOW TAG VALUES from "autogen"."kubernetes_pod_container" with key in ("host")) ;

But it is obviously not working and I can not understand is it possible in general or not.

Thanks