I don't recommend using this flash no matter how many gadgets you get trying to make it work. The problem is there is no way to control the light output because it must interface with the Canon body to work in auto mode. You'll just get frustrated and still not get a properly exposed photo.
If you want something that will work you can get something like a Nikon SB-15. It has two Auto modes where all you need to do is set the ISO on the flash, put the flash in Auto 1 or Auto 2 and the flash will tell you what to set the lens aperture to. You can get one in excellent condition for about $12. I got one that came with an old film camera I bought on ebay. It works perfectly on my D3200.
I don't know about Canon flashes frying Nikon cameras but some very old flash units had very high sync voltages and could fry any modern digital camera. The old Vivitar 283 is one that comes to mind.