Another widely accepted variation of the meaning is a slang way to assure the state of things is entirely fine; an expression of reassuring goodness. Also used as a way to introduce an effect or say "hey whatdya know--".
In "That '70s Show", Donna Pinciotti said coo coo ca choo as an end to a random string of rhymes while stoned.
Coo coo ca choo was also used by Crush the turtle in "Finding Nemo".
I am the eggman, they are the eggmen.
I am the walrus, goo goo g'joob.
--The Beatles' "I Am The Walrus"
Hide it in a hiding place where no one ever goes
Put it in your pantry with your cupcakes
It's a little secret, just the Robinsons' affair
Most of all, you've got to hide it from the kids
Coo coo ca choo Mrs Robinson
--Simon & Garfunkel's "Mrs. Robinson"
Little dudes are just eggs, leave 'em
on the beach to hatch, then coo-coo-ca-choo, they find their way back to the big 'ol blue. --Crush from "Finding Nemo"
"Everything is all right." "No worries." "All is good."
Jesus loves you more than you will know." --Simon and Garfunkel's "Mrs. Robinson"
"I am the bugman, coo coo ca choo" --The Beales' "I Am the Walrus"