I have a *Samsung SSD NVME * drive with Windows 10 on it. Can I use this drive in combination with an external enclosure (like Icy Box 1817M-C31) to boot into Windows 10 on a ThinkPad x230?
You do understand you will be connecting an NVMe SSD to a USB 3.2 Gen 1 port. USB 3.2 Gen 1 is also known as USB 3.1 Gen 1 and also USB 3.0. This will obviously come with huge performance costs. However, a USB enclosure that specifically indicates supports NVMe can be used with your machine.
Outside of Windows To Go, it's extremely tough to boot Windows on an external drive on any device. Windows to Go was discontinued over 2 years ago by Microsoft because its performance was abysmal. Windows To Go required specific storage devices to event install through the built-in capabilities of Windows 10 Enterprise.
When booted from an external device, Windows will most likely be considered a Windows To Go installation. Rufus continues to support the creation of Windows To Go devices. Sadly, I will be unable to confirm if Rufus will treat an NVMe device connected through that adapter as a removable drive.
It's not about the enclosure, but if it's possible to boot into Windows 10 from an external drive on a ThinkPad x230 through USB. (I need a workaround because the x230 doesn't come with a USB-C port or internal adapter for an SSD NVME drive)
It's doubtful that you will be able to install Windows to the device and boot from it. I suspect due to it being an external device, WinPE will not even offer the device, as something Windows can be installed to. This is due to the fact Windows does not like being installed on external removable storage devices. Windows To Go was the solution to that problem, which was discontinued since the performance was abysmal.
Even if you are able to install Windows and boot to the installation contained on the device, you will find that the Windows will be extremely slow. You shouldn't have a problem using it as an external SSD storage device.