Do you mean a PCIe card which has M.2 NVMe slots, like these:
https://www.overclockers.co.uk/pc-components/adapter-cards/m.2
(Although that category has some SATA only adapters too.)
I'm using something similar to mount a Corsair MP510 in my ancient Asus Z77 Ivy Bridge era motherboard. As long as you don't need to boot of the drives, these are fine.
Do I need to get a thermal pad for it too?