Do you expect 2000 and 3500 year old texts to have the word nuclear?
When it is both the sun and the moon affected, it is obviously atmospheric blockage producing the darkening.
The red darkening of the sun and moon have been observed from nuclear blasts.
Do you think John also saw scorpions with men’s faces flying, or was it military helicopters? (or?)
Clearly you are confusing the plain text with
shalom b'SHEM Yah'shua HaMashiach
either your own or someone else's speculation.
This could have numerous causes, not just nuclear weapons. Volcanic activity, a large meteor strike or strikes, even very large forest fires. You're reading something explanatory into the text that actually isn't there. I tend to lean toward a large meteor strike due to other passages that would appear to support such an explanation. A burning mountain falling into the sea, opening the pit, etc.