No. When you purchase support from Vmware, they are your support contact and they will escalate support to Cisco on your behalf if needed. This is the case for all OEM support. Cisco provides support for RHEL, Microsoft and VMware. We follow the same practice.
Deciding who to purchase support from is a decision of single point of contact for all VMware & N1K related issues vs. maintaining separate support contracts with each vendor individually.
Regards,
Robert