To you it is nonsense to the believer it is fact and hope in our Lord and Saviour Jesus Christ. If you notice we are not predicting the day and/or hour we are only looking at the world in general and comparing that image to what the scriptures tell us it will be when the Lord returns is all. Even Jesus said in his earthly ministry that he didn't know and the angels didn't know only his father which was in heaven knew the day and the hour of his return. Now does that satisfy you?
AND, nuclear holocaust is so similar to fire and brimstone. Maybe that is what's scaring you, so that you find a final redemption to be a necessity.