The Nitro Launcher is given to Ratchet for free on Veldin. With use, the Nitro Launcher can be upgraded to the Nitro Eruptor at V5, a weapon with greater power and blast radius. In challenge mode, it can be upgraded to the Mega Nitro Eruptor from any vendor for 380,000 bolts.
The Nitro Launcher is a fairly short silver and black grenade launcher with a few glowing blue highlights and a green left-hand grip. The Nitro Eruptor is a longer weapon with longer spikes, and launches grenades which release energy spikes similar to shrapnel in each explosion.
When the Nitro Launcher grenade explodes, the nearby space seems to move to the center of the explosion. This suggests that, despite the name, the weapon does not use nitroglycerin, but another, more advanced substance.
The Nitro Launcher has a good blast radius and is powerful, but has very limited ammunition. Early on, the Launcher is very useful in situations against groups of enemies close together, or against larger bosses, though its low ammunition means it should not be relied on. Later on, the Nitro Launcher is outclassed by explosive weapons which fire faster, have greater ammo and greater damage, such as the Annihilator and the Bouncer.
The Nitro Launcher gains features with levels over time. At V2, it adds a damage over time effect on enemies hit by it. At V3, it can lock on to enemies. At V4, its blast radius increases. At V5, as the Nitro Eruptor, it has a huge blast radius with energy shrapnel. As the Nitro Launcher is useful early on, it should be upgraded soon.