To a large extent, show assent about menu’s content (2,3)

I believe the answer is:
no end
'to a large extent' is the definition.
I can't judge whether this definition defines the answer.
'assent about menu's content' is the wordplay.
'assent' becomes 'nod' (I've seen this in another clue).
'about' means one lot of letters goes inside another.
'content' means to look at the middle letters.
The centre of 'menu' is 'en'.
'nod' placed around 'en' is 'NO END'.
'show' is the link.
Can you help me to learn more?
(Other definitions for no end that I've seen before include "what eternity offers?" , "goalless?" , "Non-stop" , "detailed?" , "A lot" .)
