Not a containers expert and I never used docker swarm, but I will still go with Nomad for container orchestration over Kubernetes anytime I can, gets the job done with minimal fuss.
See my three rules above. Engineering is a zero sum game, even in open source. Nomad has a very dark future. Single vendor, no community, very little usage, no competitors adopting the tech. If your competitors don't adopt your tech is dead (basic open source 101)...
Would you still do this even if you had K8s available as a managed service?