The Nitro Launcher is given to Ratchet for free on Veldin by the Galactic Rangers. 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 Gadgetron 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 upgraded Nitro Eruptor is a longer weapon with longer panels and launches grenades which release energy spikes similar to shrapnel in each explosion. When the Nitro Launcher grenade explodes, the nearby space is temporarily sucked in to the center, before being violently caught in the blast radius. At V3 the blast radius also changes colors from a bright blue to orange.
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 mobs of enemies clustered together, or against larger bosses where its damage is useful, though its low ammunition means it should be used sparingly. Later on, the Nitro Launcher is outclassed by explosive weapons which fill similar roles but fire faster, have greater ammo, and more damage, such as the Annihilator and the Bouncer.
The Nitro Launcher gains features with levels over time. At V2, it adds an acidic 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, though it can still provide some use later on for a few fights due to its sheer power and area of effect by knocking back enemies.