BTW , since you have a Z170 motherboard (if your profile is up to date) it should support NVME boot out of the box.
Even my Z97 supported it so i don't see why you couldn't boot from it.
I'm not really sure about your situation but i successfully cloned my Windows 10 from my old boot SSD to my 970 EVO M.2 2280 a while back.
For that i used Samsung Data Migration software.