OPTE needs to be set up to respond to Router Solicitations (on both the all-routers broadcast and its unicast address). The Router Advertisements it shoots back need to instruct the host that OPTE is the default (well, only) router, and that the host needs to use DHCPv6 to get both its VPC-private IPv6 address and the DNS servers.
There shouldn't be much else, OPTE doesn't need to provide any on-link prefixes. OPTE may need to make sure the host's SLAAC procedure doesn't somehow pick the same IP as OPTE itself, but that's very unlikely since the host should be using an EUI-64 transform on its (Nexus-provided) MAC address to derive it's link-local IPv6 address. Since OPTE sets itself up as the only router, and there's nothing else on-link, there shouldn't be any address resolution needed.
OPTE needs to be set up to respond to Router Solicitations (on both the all-routers broadcast and its unicast address). The Router Advertisements it shoots back need to instruct the host that OPTE is the default (well, only) router, and that the host needs to use DHCPv6 to get both its VPC-private IPv6 address and the DNS servers.
There shouldn't be much else, OPTE doesn't need to provide any on-link prefixes. OPTE may need to make sure the host's SLAAC procedure doesn't somehow pick the same IP as OPTE itself, but that's very unlikely since the host should be using an EUI-64 transform on its (Nexus-provided) MAC address to derive it's link-local IPv6 address. Since OPTE sets itself up as the only router, and there's nothing else on-link, there shouldn't be any address resolution needed.