The linked Wikipedia article discusses the effect of the electromagnetic pulses produced by the blasts.
unless protected, with lead coating for example
The electromagnetic pulse is like a radio wave, not ionizing radiation. You need extremely effective electrical shielding not radiation shielding.
This answer to Would astronauts on the ISS be affected by the radiation from a global nuclear war? and to a lesser extent this answer to Can people be in orbit around Mars were they to blast the poles with Nuclear bombs? discuss the phenomenon.
As explained in the link above and here if a deliberate EMP device was used, the burst would be at high altitude in the atmosphere or in space. The prompt gamma ray pulse propagates to the thicker atmosphere where the electrons in the atoms of the atmosphere all jump at once, producing a lower frequency electromagnetic transient. That will propagate back up to the ISS' 400 km and if it's passing over the footprint of the EMP device it may get zapped.
In your example the blast is at the surface so that's where the EMP would originate.
Briefly, the intense gamma ray burst knocks electrons out of atoms in the atmosphere via Compton scattering and the sudden pulse of those electrons makes an electromagnetic wave a bit like a radio wave except very short and broad in frequency.
This is picked up by wires and electronics and makes a current that tends to burn out devices, especially semiconductors.
Satellites in LEO that are passing overhead will receive this electromagnetic pulse but it's really hard to say how many or which ones would be affected; technology gets better over time.
With how the satellite density has increased since the ban on nuclear tests, I'm assuming a few would be affected.
This could be the case.