Because the liquid-to-gas expansion ratio of nitrogen is 1:694 at 20 °C (68 °F), a tremendous amount of force can be generated if liquid nitrogen is rapidly vaporized in an enclosed space.
Why Do Explosives Have Nitrogen In Them?
Akash Peshin 22 Jun 2018 (Updated: 16 Apr 2019)
The use of nitrogen in an explosive is ironic because a molecule of nitrogen gas (N2) represents one of the most stable bonds we have ever discovered. If nitrogen is explosive, why hasn’t the atmosphere, which is mostly nitrogen, ever succumbed to devastating explosions?
Still, if it weren’t for nitrogen, TNT or dynamites would have been about as explosive as cheese or sand. So, what then makes nitrogen the magic ingredient?
https://www.scienceabc.com/innovation/why-do-explosives-have-nitrogen-in-them.html