It gave the Chiefs a 10-6 lead, but ill discipline gave Fouche two kickable penalties to get his side back into the game.
A turnover ball was pounced on by Aaron Cruden who fed Glen Fisiiahi, only for the winger to be caught close to the line.
But the position wasn't wasted and the ball was fed to McKenzie who scored. Moments later the Chiefs were in again with the extremely lively Brad Weber instrumental in getting Seu over.
The Kings showed character in scoring the final try of the half through Edgar Marutlulle to go in 27-17 down at the break.
The Chiefs effectively killed off the contest with early second half tries to Charlie Ngatai and Cruden, both from Kings' errors.
When Martin Bezuidenhoult was sin-binned in the 69th minute, the prospect of a huge score was strong but, to their credit, the Kings conceded only one more try while down to 14, the final points coming from a penalty right on full time.
The bonus point win puts the Chiefs second behind ACT in the Australasian group.
They now travel to take on the Jaguares in Argentina next weekend.
Scores:
Chiefs 58 (Sam Cane 2, Aaron Cruden, Glen Fisiiahi, Damian McKenzie, Charlie Ngatai, Taleni Seu tries McKenzie 7 con, 3 pen) Kings 24 (Edgar Marutlulle 2 tries Louis Fouche con, 4 pen) at Nelson Mandela Bay Stadium. Referee: Jaco van Heerden.