Chamber piece, after reductions, needing almost twelve around (7)

'chamber piece after reductions' is the definition.
I know nothing about this answer so I can't tell whether this works.

'needing almost twelve around' is the wordplay.
'needing' becomes 'nett' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'almost' means to remove the last letter (almost the whole word is kept).
'twelve' becomes 'noon' (twelve noon).
'around' means one lot of letters goes inside another.
'noon' with its last letter taken off is 'noo'.
'nett' going within 'noo' is 'NONETTO'.

Can you help me to learn more?