Chaos Nemesis is a Mark-4 Jaeger.
Pacific Rim: The Black
At some point, Chaos Nemesis is presumably destroyed by a Kaiju. Its right arm is removed by Apex and given it to Atlas Destroyer as a replacement for its original right arm, which was previously eaten by Category IV Kaiju Copperhead.
Not much is known about Chaos Nemesis's arsenal other than its arms are very durable and come with Vanadium Steel Saber Chain.