I was listening to a history documentary (A Distant Mirror) and it went over a group of Peasants, who were nicknamed after their armor, that killed a bunch of nobles but I can't remember what they were called.

by BloodFartThePirate

It was something like Jack but it was pronounced with that sort of nasally J sound. I was really interested in them but I can't figure out where to look.

Valkine

They are probably referring to the Jacquerie, a movement that exists somewhere in the grey space between rebellion and broad societal breakdown. The term was pretty catch-all, and doesn't really refer to a singular group with unified membership and cause. While members are often referred to as 'peasants', they could easily have included former soldiers turned to banditry and members of a broader swath of society than simple farmers. While they almost certainly killed some nobles, their success is probably overstated, and certainly more of them died in their eventual suppression than they ever killed.

Jean le Bel is a very hostile, but very interesting, primary source for the rebellion. His account is very closely copied into Froissart's Chronicles, and may be most easily accessed there. I'm not sure what the state of publications for le Bel's chronicle is, but Penguin has a decent abridged version of Froissart.

For secondary material, I highly recommend David Green's The Hundred Year's War: A People's History. It covers the war very generally, but then digs into the societal impacts of the conflict and its broader cultural implications. He doesn't cover the Jacquerie in great detail (their revolt really only lasted a matter of weeks), but he does devote an entire chapter to the peasantry around the time of the Jacquerie rebellion and helps to put them (and other similar rebellions) into their broader context.