This message was posted on behalf of Intel Corporation
marjo: Thank you very much for contacting the Intel® NUC communities. We will do our best to provide the information you are looking for.
In regard to your inquiry, yes, you can use your existing SSD on the Intel® NUC7i3BNHX1, just make sure to enable the optane feature in the BIOS, to use Windows® 10 and SATA-based boot drive. On the following link you will find additional details about the feature:
Any further questions, please let me know.
Obviously, if this SSD is an M.2 SSD, you would have to remove the Optane Memory module to use it -- and, in this case, disable the Optane feature in the BIOS.