Ronnie Coulter was found guilty at the High Court in Glasgow earlier this month of stabbing the 32-year-old almost 18 years ago.
The attack happened as Mr Chhokar returned from his work at an Indian restaurant in Wishaw, North Lanarkshire, on November 4, 1998.
Coulter, 48, was previously acquitted when he stood trial in 1999 for the murder but was convicted by a majority when the case became only the second to return to court since Scotland’s centuries-old double jeopardy law was reformed in 2011.
He was sentenced to life at the same court on Monday, with a minimum term of 19 years and eight months.
Judge Lord Matthews said Mr Chhokar was the “victim of an ambush that cost him his life”.
In passing sentence, he said the violent attack was not “spur of the moment” but had been discussed by Coulter earlier in the day.
He praised the patience and “quiet dignity of the Chhokar family”.
Lord Matthews said: “It is plain that the only purpose was violence.
“You inflicted three stab wounds in what was a despicable and cowardly act.”
In mitigation, Coulter’s representative Donald Findlay QC said his client maintains that he was at the scene but did not “wield the knife”.
Mr Findlay also said race “had no part whatsoever to play in this matter” and urged Lord Matthews to judge on “the facts of the case” and exercise leniency in respect of Coulter’s treatment for depression and paranoid schizophrenia.