The 16-year-old from Motherwell, North Lanarkshire, moved the crowd and judges of the ITV show with his rendition of A Thousand Years, by Christina Perri.
But before his sterling performance at London's Wembley Arena, he revealed his insecurities when he said that the other contestants looked like pop stars and he looked "like a wee Scottish guy".
Nicholas said he had been practising his song every day and his preparation paid off as the strong performance earned him a standing ovation and four yes votes from the celebrity judges, sending him to Bootcamp. Nicole Scherzinger said the performace was "bellisimo". Gary Barlow added: "You knocked it out of the park".