hello , i try to use dot1q tunnel to pass vlan 20 thought dot1q tunnel.
i create the config as above image we make ping from host 1 [10.10.10.1] to host 2 [10.10.10.2] i get unreachable , i go to deep about packet analysis
i use wireshark software at interface 1/2 bewween Host1 and sw-bng
i notice the packets is have one tag only  so he must have two tag , first 10 for tunnel then 20
i try make wireshark analysis at e1/1 between sw-bng and nexos but that's no packet is pass
i use nexos 9000 in eve .
Have you configured " spanning-tree port type edge " on the Eth1/2?
Also, the capture file seems ok, as it is expected to receive the traffic with only one tag and that one being vlan 20.
The double tagging should be observed on the trunk only
P.S. there is a dedicated data center community, with Data Center Switches sub-community. https://community.cisco.com/t5/data-center/ct-p/4436-data-center For all Nexus related questions, you can get better visibility there.
I am not sure if it will solve the problem, but as per config guide, must be configured:
You must set the 802.1Q tunnel port to an edge port with the spanning-tree port type edge command. The VLAN membership of the port is changed using the switchport access vlan vlan-id command.