The former deputy PM told the BBC the company had carried out analyses of its data and found no "significant attempt" by outside forces to sway the vote.
Instead, he argued that "the roots to British euroscepticism go very deep".
In a wide-ranging interview, Sir Nick also called for more regulation of Facebook and other tech giants.
Sir Nick, the former leader of the Liberal Democrats and deputy prime minister during the Coalition government, was hired by Facebook in October last year.
In an interview with BBC Radio 4's Today programme, he said Facebook was now arguing for greater ...
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