I upgraded my xps 13 256 Gb storage to 512 Gb using Mr. Devine's 2016 article.

[Windows Central Question]

I have the old 256 Gb SSD but my computer won't "see" it. It's Toshiba part KXG50ZNV256G, and the Geek Squad guy says I need an NVME M.2 PCI express enclosure. Is that correct?
I can't find that anywhere? I also don't understand the issue so I don't know wht alternatives may exist. Any thoughts or wisdom you can share??