NSX manager does not have to be in the same subnet as ESXi hosts and vCenter but should be able to communicate with them. Per the NSX Design Guide:
The NSX manager requires IP connectivity to vCenter, controller, NSX Edge resources, and ESXi hosts. NSX manager typically resides in the same subnet (VLAN) as vCenter and communicates over the management network. This is not a strict requirement; NSX manager supports inter-subnet IP communication where design constraints require subnet separation from vCenter (e.g., security policy, multi-domain management).
In short, don't put vCenter or NSX manager on a logical switch. Keep them on a VLAN or VLANs that are routed by your physical network. Hope that helps.
