The Battle of Nal Kapok was fought on the planet of Nal Kapok during the period of the Clone Wars. The combatants were the Confederacy of Independent Systems against the forces of the Galactic Republic. According to R0-GR, a B1-series battle droid who had served throughout the Clone Wars, this particular engagement was the most awful that he had participated in.
The first mention of this battle occurred in the initial episode of LEGO Star Wars: The Freemaker Adventures, a TV series considered non-canon. Subsequently, it achieved canonized status via the reference book Star Wars: Droidography, published in 2018.