They used a radiological weapon, that's nuclear technology and must contain serious nuclear material for the damage it did; so Caesar has actually used nuclear weapon.
Who is more likely do discover how to manufacture Nukes.
A faction dedicated to old world way of life.
A faction that decides depending on Technology is weak.
Yes Caesar used a Rad weapon. Are you saying NCR wouldn't?
There are only a certain amount of Nukes left in the world but to be honest NCR would be closer to discovering how to manufacture them.