chaos, pandemonium
[noun]
[de hek-sen-ke-tel, de hek-sen-ke-tels]

"Heksenketel" is composed of "heks" and "ketel", which respectively translate to "witch" and
"cauldron/kettle". "Heksenketel" therefore literally translates to "witches’ cauldron". However…unless you’re reading a Harry Potter book, you will only hear "heksenketel" being used in its figurative meaning: a place or situation with (lots of) confusion and disorder: a chaos or pandemonium.

Examples:
– "Het was vanochtend een heksenketel op de Nederlandse wegen." 
("It was chaos on the Dutch roads this morning.")

– "Tijdens de Drie Dwaze Dagen is het altijd een heksenketel in de Bijenkorf." 
("During the Three Mad Days it’s always a pandemonium at the Bijenkorf department store.")

– "Na de wedstrijd Ajax-Feyenoord was het weer een enorme heksenketel rond het stadion." 
("After the Ajax-Feyenoord match it was a big chaos again around the stadium.")

Expressions:
– "Heksen": lit.: to perform witchcraft [verb] [hekste, gehekst]. Fig.: to do the impossible.

Example:
– "Je moet als de wiedeweerga je koffer in gaan pakken, anders halen we het vliegtuig niet" – "Rustig, rustig, ik kan niet heksen!"
("You have to pack your suitcase on the double, otherwise we’ll miss the plane" – "Slow down, slow down, I can’t do the impossible!")

Related words:
– Heks: witch [noun] [de heks, de heksen].
– Ketel: cauldron, kettle [noun] [de ketel, de ketels].
– Bezem: broom [noun] [de bezem, de bezems].

Example:
– "De bezem van Harry Potter is een Nimbus 2000…de snelste in zijn soort…"
("Harry Potter’s broom is a Nimbus 2000…the fastest of its kind…")

– Heksenjacht: witch hunt [noun] [de heksenjacht, de heksenjachten].
– Hekserij: witchcraft [noun] [de hekserij, <no plural>].

Extra:
The Harry Potter books are immensly popular in the Netherlands too. Except for Harry, Voldemort and Hagrid, the translated names of the characters (and other things) differ quite a lot from the original English names. Here’s a brief overview:
– Harry Potter : Harry Potter
– Ron Weasly : Ron Wemel
– Hermione Granger : Hermelien Griffel
– Hagrid : Hagrid.
– Albus Dumbledore : Albus Perkamentus
– Voldemort : Voldemort
– Severus Snape : Severus Sneep
– Draco Malfoy : Draco Malfidus
– Gryffindor : Griffoendor
– Slytherin : Zwadderich
For an extensive overview, check this link.