The deal is expected to be announced this week.
According to Reuters, Pochettino will take charge of the club at the end of the season, the reports said, succeeding Frank Lampard who took over as interim manager at Stamford Bridge last month following the sacking of Graham Potter.
Chelsea have lost six of their eight matches under Lampard, leaving them 11th in the league standings and without European football for next season after their quarter-final exit from the Champions League.
The London club won the Champions League in 2021, but will end this season without any silverware and are stumbling towards their worst campaign since 1993-94 when they finished 14th under Glenn Hoddle despite their new U.S. owners’ huge outlay on players.
Pochettino, who favours a high-pressing and attacking style of play, will be tasked with reviving their fortunes.
The 51-year-old Argentine garnered a reputation for fostering young talent and led Southampton to an eighth-placed finish in his first full season in England before joining Spurs in 2014.
Under Pochettino, Tottenham reached the 2019 Champions League final and became Premier League title contenders as they finished in the top four for four straight seasons from 2015-19 before he was fired.
Pochettino joined PSG in January 2021, winning a French Cup and a Ligue 1 title, but he was sacked after failing to deliver in the Champions League.