Jaiswal took the Nepal bowling attack to the cleaners.
Jaiswal, at 21 years nine months and 13 days, broke the record previously held by Shubman Gill, who slammed a T20I ton against New Zealand at the age of 23 years and 146 days.
The southpaw took 48 deliveries to notch up his maiden T20I hundred in his sixth appearance in the shortest format. He reached the three-figure mark with a single off Sompal Kami in the 16th over.
Jaiswal failed to convert his whirlwind century to a big one, getting out on 100 off 49 balls. His knock was studded with 8 fours and 7 sixes.
With this innings, Jaiswal became only the eighth Indian batter to register a T20I hundred after Gill, Virat Kohl, KL Rahul, Rohit Sharma, Suryakumar Yadav, Deepak Hooda and Suresh Raina.
Riding on his century and a couple of cameos from Rinku Singh (37* off 15) and Shivam Dube (25* off 19), India piled up a mammoth 202/4 on the board.
Defending the total, Indian bowlers restricted Nepal to 179/9 to win the contest by 23 runs. Leg-spinner Ravi Bishnoi starred with the ball for India, claiming three wickets by conceding 24 runs in his four overs. Pacer Avesh Khan also returned with the impressive figures of 3 for 32 in his four overs.