In the last 75 years, two nuclear weapons have been detonated as an act of war; the bombings of Hiroshima and Nagasaki in 1945, at the end of WWII. Despite tensions being high between the US and the USSR during the Cold War, and several close calls, there have been no additional nuclear weapons detonated as acts of war.
Currently, estimated nuclear weapon stockpiles are 15,000 warheads worldwide, mostly in the US and Russia, and there are eight or nine states that possess nuclear weapons (China, France, Russia, United Kingdom, United States, India, North Korea, Pakistan, and Israel which remains officially ambiguous). The use of these nuclear weapons could be catastrophic.
This question asks:
Will more than two nuclear weapons in total have been detonated as an act of war by 2050?
Resolution will be by credible media reports. Only deliberate nuclear attacks by nations count for the purpose of resolution. Attacks using strategic and tactical nuclear weapons are both sufficient to qualify.