The 24-year-old West Indian, who played in three of the five matches in the tournament's 2019 edition, will be available for the majority of the Vikings' North-Group matches in 2020, subject to international commitments.
"I look forward to catching up with my team-mates in 2020."
Pooran has amassed 2278 runs in 119 T20 matches, averaging 24.49, including 12 fifties.
Yorkshire County Cricket Club's First XI Coach (Andrew Gale) rates Nicholas Pooran highly as a player and reckons he can be a match winner on his day. "We all got a glimpse of what a special player he is (last season); he is box office. In T20 cricket, you always look down the team sheet to see who can win you a game, and Pooran is a guy that can win you a game on his own."