HSS will work triggered optically with the Nikon Commander for remote HSS flashes. However, the internal flash cannot do HSS itself, so the commanders builtin flash group must be disabled (with mode "- --), so it does Not try to contribute light (internal flash cannot do HSS). Then the commander can do its HSS stuff, and the internal flash will flash commands. It works.  

If you are able to set 1/8000 second with commander, you surely already have the built-in flash disabled.  Otherwise, shutter speed will revert back to 1/250 sync speed when you open the internal flash door.  

But the remote flash must also be set to its commander-compatible mode, which does NOT include the dumb optical slave modes.

The reason you see the remote flashing is this:

The commander first sends various early flashes, the command to set power level in the remote group, or to request TTL preflash in the remote group and commands to set its power.  Then after all this setup completes, then the shutter opens and the triggering flash.  However, any flash incorrectly in its own dumb optical slave mode will have already flashed when the early commands are seen, before the shutter opens.

Look for the flash menu to enable the trigger mode compatible with the commander. That menu surely also has choices to set Channel and Group, to be compatible with the commander settings.