Effectively ... ANYONE who's 16 years of age or older and has been domiciled in Scotland for two years or more will be entitled to vote - regardless of whether they're native-born or naturalised British Citizens.
Conversely, this privilege is NOT extended to those who - on the date of the Referendum - are living either abroad, or even in England, Wales or Northern Ireland ... ... irrespective of the fact that Scotland happened to be their birthplace.
I hope the foregoing statement makes sense.