Scotsman and nearly all his people making plot (11)

'plot' is the definition.
(I know that machination is a type of plot)

'scotsman and nearly all his people' is the wordplay.
'scotsman' becomes 'mac'.
'and' is a charade indicator (letters next to each other).
'nearly all' means to remove the last letter.
'people' becomes 'nation' ().
'his' with its last letter removed is 'hi'.
'mac'+'hi'+'nation'='MACHINATION'

'making' acts as a link.