...Is nuclear war in prophecy?...
In the coming tribulation I believe we need to be prepared to see the possible use of nuclear weapons, which may be represented by the "great sword" of the 2nd horseman in Revelation: "And there went out another horse that was red: and power was given to him that sat thereon to take peace from the earth, and that they should kill one another: and there was given unto him a GREAT SWORD" (Revelation 6:4). Note that Revelation 6:8 says 1/4 of the earth dies as a result of this warfare and its resulting famines.
Other Biblical passages may also be describing the use of nuclear weapons: "Fire, and PILLARS OF SMOKE. The sun shall be turned into darkness, and the moon into blood, before the great and terrible day of the LORD come" (Joel 2:30-31).
"So the king of the north shall come, and cast up a mount, and take the most fenced cities: and the arms of the south shall not withstand, neither his chosen people, NEITHER SHALL THERE BE ANY STRENGTH TO WITHSTAND. But he that cometh against him shall do according to his own will, and none shall stand before him: and he shall stand in the glorious land, which by his hand SHALL BE CONSUMED" (Daniel 11:15-16).
"Son of man, set thy face toward Jerusalem, and drop thy word toward the holy places, and prophesy against the land of Israel, And say to the land of Israel, Thus saith the LORD; Behold, I am against thee, and will draw forth my sword out of his sheath, and will cut off from thee the righteous and the wicked. Seeing then that I will cut off from thee the righteous and the wicked, therefore shall my sword go forth out of his sheath AGAINST ALL FLESH from the south to the north: That all flesh may know that I the LORD have drawn forth my sword out of his sheath: it shall not return any more. Sigh therefore, thou son of man, with the breaking of thy loins; and with bitterness sigh before their eyes. And it shall be, when they say unto thee, Wherefore sighest thou? that thou shalt answer, For the tidings; because it cometh: and EVERY HEART SHALL MELT, and all hands shall be feeble, and every spirit shall faint, and all knees shall be weak as water: behold, it cometh, and shall be brought to pass, saith the Lord GOD. Again the word of the LORD came unto me, saying, Son of man, prophesy, and say, Thus saith the LORD; Say, A sword, a sword is sharpened, and also furbished: It is sharpened to make a sore slaughter; it is furbished that it may glitter: should we then make mirth? it contemneth the rod of my son, as every tree. And he hath given it to be furbished, that it may be handled: this sword is sharpened, and it is furbished, to give it into the hand of the slayer. Cry and howl, son of man: for it shall be upon my people, it shall be upon all the princes of Israel: terrors by reason of the sword shall be upon my people: smite therefore upon thy thigh. Because it is a trial, and what if the sword contemn even the rod? it shall be no more, saith the Lord GOD. Thou therefore, son of man, prophesy, and smite thine hands together, and let the sword be doubled the third time, the sword of the slain: it is the sword of the great men that are slain, which entereth into their PRIVY CHAMBERS. I have set the point of the sword against all their gates, that their heart may faint, and their ruins be multiplied: ah! IT IS MADE BRIGHT" (Ezekiel 21:2-15).