I was using an aircraft carrier, but yeah, that was where I was going wrong. I thought the icon would be on the heavy bomber itself. But it was on the aircraft carrier. But I can't figure out why I wasn't able to nuke a certain Hatshephut city. It's kind of strange what cities it will let you nuke, and which ones you can't. It has no problem letting you nuke your own cities. And yes I was at war, and also declared on Ibn who also had troops next to that city I was trying to nuke, but the game wouldn't let me. And radioactive fallout in the oceans is kind of funny. Makes sense, but still funny.