Philip, Check out Page 6 of Nimble's "VMware vSphere® 6 Deployment Considerations" guide at https://cdm-cdn.nimblestorage.com/2016/12/08171022/Nimble-VMware_vSphere6-DeploymentConsiderations.pdf With either recommended iSCSI connection method...
Philip, I would tend towards connecting the Nimble with a dual subnet design. Your iSCSI-A subnet would live on X620-A and your iSCSI-B subnet would live on X620-B. Each host and Nimble controller would have an interface on each iSCSI subnet/swi...