Det Supt Lewis Basford, who led the Met Police’s investigation, said the offences had caused “deep shock and distress”.
The force said it was one of the most complex and disturbing cases that officers had investigated.
Chan started work at the nursery in 2017 and took on a number of roles including art specialist, room leader and nursery nurse.
He was entrusted with the care of children aged between two and four.
Chan first came to attention for filming the children in his care and overlaying the video with audio.
Family members of many of the victims sat in the dock as charges were read out, many of them in tears.
