It’s possible that Nixon was almost as criminal - he was pardoned in advance of that being tested, so we’ll never know - but this is way beyond a ‘scandal’.
It’s been handled very cleverly, with the indictment not being unsealed until all the heat and froth arising from the first announcement had started, and thus taking the wind out of a lot of sails.
However, there is always the risk that bringing this to trial takes so long that Trump is re-elected beforehand, and the ludicrous tradition of not prosecuting sitting presidents kicks in.