This dock uses the original Nexus 5X charging cable. Just push the cable through the hole and use the clip to hold it in place. Everything is friction fitted.
There are two versions: The naked version is for phones without any case and the other version is for my transparent, flexible case. I am assuming it would fit for most cases of this type, but obviously I can´t give any guarantees.
Printed with 20% infill and ABS on a Repetier hacked XYZ Davinci 1.0
Update: Added another version for wider cases in STL format - 75.4mm wide.