Nomad and Kubernetes orchestrate Linux containers using features of the Linux kernel (except where Windows kernel support has also been added).

Maybe you're thinking of jails? I'm not sure if there's any mainstream/popular distributed orchestration systems for those.

Okay... can you name a specific thing? I'm confused. Nomad and Kubernetes both support Windows workers well. Kubernetes, afaik, doesn't support something like OpenBSD in a common flavor like RKE.