Sokovia explosion was multiple times stronger. We have dropped thousands of nuclear weapons, bothon the grouns and below the ground, none have done anything like destroy a massive landmass like that, not even close. The only part that a regular nuclear warhead could replicate would be the initial and after damage of when the lightning bolt touched down and atomized the city.
The vibranium core is key part here though, without core running through whole city, at best Thor may have split the landmass and destroyed Sokovia.
Power output of Sokovia vs nuke=mjolnir>>nuke probably not by a lot tho
Durability needed= Sokovia->>>>nuke
Fragmentation, atmosphere, friction etc. Supes took a portion of the nukes force in space. Thor took that straight to face with fragmentation, and heat added.