Nobel created his prize because everyone knew him for creating bombs and he wanted to be remembered for doing something good. Awarding someone a Nobel prize for creating a giant bomb would be pretty ironic.
To be fair, had he lived longer then he would have received a Nobel prize for his work in astro physics in relation to gravitational collapse. This work would later become far more important than his other work as his contributions would lead to the discovery of black holes
That's a lie that the US government has desperately been trying to push for decades. The creation and detonation of nukes was an entirely avoidale atrocity.
The truth is we can't know for sure. There's no way to look into an alternative timeline to see what the Cold War would have been like without nukes as deterrents.
@Zirconium said "probably" and you flat out called it a lie, so you're more wrong than they are.
Shaun made an excellent video on the topic, although you're going to have to invest a lot of time into watching it. It's got a good selection of sources, too, for those of you who love to hold on to the common narrative that dropping the bomb was necessary.