An EMP is just a sudden change in the electric and magnetic fields, which on its own isn’t too bad. The way you generate an EMP (or any interesting electromagnetic effect) is you get a bunch of charge and suddenly move it. A nuclear weapon on its own doesn’t have a bunch of extra charges to move around, but luckily (unluckily?) It’s worth mentioning that nuclear bombs aren’t the only thing that cause these sorts of large-scale electronic nastiness. The results are the similar to a nuclear EMP, but global and toned way down.