and also, can I use the YN467 for Canon on a Nikon DSLR?
TTL flashes must use the proprietary hotshoe signalling system of the camera it's mounted on to communicate with the camera to perform TTL. So, the differences between the Canon and Nikon versions of a Yongnuo TTL flash, physically, is the pin layout on the foot, and the electronic signal internals.
Since most people don't pay attention to the pins on the foot of a flash, Yongnuo always uses gold lettering on Nikon versions of their TTL flashes, and silver lettering on their Canon versions. (See: Are Yongnuo flashes interchangeable between dslr's or are they brand specific?).
If you swap Canon/Nikon, the issue is that none of the non-sync pins make contact on the hotshoe. The sync pin is the one in the center of the "square" of the foot. That is part of an ISO-standard, which also dictates the dimensions of the hotshoe and foot, and all current new hotshoe flashes adhere to that standard, so flashes can work across brands.
But, the only signal that can be communicate from the camera to the flash is the sync (fire!) signal. So nothing else gets communicated: no TTL, HSS, settings adjustments from the camera menu, etc. So, it may not be worth it. And if the pins accidentally make contact you could get some signal crosstalk, so some folks will remove the non-sync pins or tape them over.
That said, all digital era flashes are typically safe from a sync voltage standpoint, as most of them are below 10V, which should be well within the safety limit of most Canon and Nikon dSLRs (typically +250V). It's only the first-generation Canon dSLRs that are limited to 6V on the hotshoe. If your camera was made after 2004, you'll be safe with any new digital-era flash. It's only vintage flashes that may be over the 250V limit.
What's the difference between Speedlite YN467 for Nikon and for Canon?
Different brands use different pin configurations on their hot shoes, so the locations and functions of pins on the version for Canon and for Nikon will be different. Also, the details of how the flash is controlled vary from one brand to another, and the different versions of the flash are designed to work with each particular brand.