How strong is a nuclear bomb in the Dragon Ball universe?

[In Brightest Day]

Apparently about as strong as Nappa when he's not even trying.

Yeah, pretty much this. Destroying an entire city with two fingers and casually surviving the blast without a scratch.

[Tsufuru]

king piccolo's blast us compared to a small nuke in the databooks.

and when was it said frieza's body helped him survive?
everything comes down to ki as said by akira toriyama and besides he only survived cuz of gokus ki.

they also have heat resistence since even a mini ki blast from kid gohan set wood instantly on fire and Freeza's ki blast burned gokus hand.
obviously the higher power the hotter it gets.

[Regarder]

Going from what I said in my initial post, possibly a nuke would have the same effect as Taiyoken on their sensitive eyes, but do no damage to their body. Light isn't much of a factor for regular ki attacks, whereas for nukes, and Taiyoken/Solar Flare, radiation/light is kind of the whole thing.

[Jabberwock xeno]

I'd wager that the actual blast itself would probably not affect them any worse then an equally sized ki attack, but the radiation would likely prove fatal to a variety of characters, it's been shown that no matter how powerful they get, they are still susceptible to magic and things like diseases, I think they would be affected by the radiation just as much as anybody else.

Saiyans might be affected less due to it being shown they can do stuff in outer space which would imply they have a higher tolerance for it, and alien races in general could be affected differently.