According the the
Canon flash compatibility list, your old flash has a trigger voltage of around 5 to 6 volts. I reckon that means it should not damage your Nikon. However check what your cameras trigger voltage is just to be sure.
If you read the bit on that page about the Centon fg105d it mentions iffy performance sometimes but that's with Canon so it may not apply.
I use an old Centon FH85 on my 300d very successfully.