Docker & OSX's guest Windows 10 Pro "doesn't have VT-X/AMD-v enabled. Enabling it in the BIOS is mandatory"

I have macOS 10.12.3 and Windows 10 Pro running under Parallels. I try to install Docker to Windows 10. I could not install Docker for Windows rather Docker Toolbox (no idea why) but in installing the Docker Toolbox

"This computer doesn't have VT-X/AMD-v enabled. Enabling it in the BIOS is mandatory"

and according to older threads, getting Docker to work may not work with VirtualBox because of lacking nested virtualisation support (this may be old).

C:\Program Files\Oracle\VirtualBox\VBoxManage.exe --version,(default) DBG |
 STDOUT:
,(default) DBG |
 {,(default) DBG |
 5.1.20r114628,(default) DBG |
 },(default) DBG |
 STDERR:
,(default) DBG |
 {,(default) DBG |
 },(default) DBG |
 Hyper-V is not installed.,(default) DBG |
 %!(EXTRA *exec.Error=exec:
 "vmms.exe":
 executable file not found in %PATH%)COMMAND:
 wmic cpu get VirtualizationFirmwareEnabled,(default) DBG |
 STDOUT:
,(default) DBG |
 {,(default) DBG |
 VirtualizationFirmwareEnabled ,(default) DBG |
 FALSE ,(default) DBG |
 ,(default) DBG |
 },Error with pre-create check:
 "This computer doesn't have VT-X/AMD-v enabled. Enabling it in the BIOS is mandatory",open 
C:\Users\user2.user\.docker\machine\machines\default\default\Logs\VBox.log:
 The system cannot find the path specified.,notifying bugsnag:
 [Error with pre-create check:
 "This computer doesn't have VT-X/AMD-v enabled. Enabling it in the BIOS is mandatory"],bugsnag.Notify:
 [bugsnag/payload.deliver:
 Post https:
//notify.bugsnag.com/:
 dial tcp:
 lookup notify.bugsnag.com:
 getaddrinfow:
 No such host is known.],

where notice that "This computer doesn't have VT-X/AMD-v enabled. Enabling it in the BIOS is mandatory" and "Hyper-V is not installed.".

How can I get Docker working in Windows 10 Pro with the host OSX and Windows 10 virtualised in Parallel software of OSX?

Older threads with different setup ands some tips

1. https://superuser.com/questions/1138980/this-computer-doesnt-have-vt-x-amd-v-enabled-enabling-it-in-the-bios-is-mandat

2. Hyper-V in Windows 10 on MacBook Pro

Instead of using BootCamp, use a virtualization system running on macOS such as VMware Fusion, Parallels, etc. You can use nested virtualization to run the Docker containers using Hyper-V on Windows that way.

Parallels settings (running Parallels Desktop 12 for Mac, version 12.2.0)

I cannot see anything about enabling nested virtualisation.

To enable nested virtualization in Parallels, do the following:

1) Shutdown the virtual machine

2) Open the configuration for the virtual machine

3) Click the "General" tab

4) Select either to auto-detect the OS, or explicitly select Windows 10

5) Click the "Hardware" tab and then click "CPU & Memory" in the list on the left

6) Expand "Advanced settings" and tick the "Enable nested virtualization" option