After ESXi 6.7, it is not able to configure nested virtualization and pci passthrough together in 1 VM.
To use the functions together, follow below steps:
1. Power off the VM
2. Unregester the VM
3. Download the .vmx file and backup 1 copy
4. Modify the .vmx, add:
vhv.allowPassthru = "TRUE" vhv.enable = "TRUE"
5. Regester VM
6. DO NOT modify the VM setting anymore