After Jharkhand captain Varun Aaron chose to field, his bowling unit restricted Kerala to 236 for eight in 50 overs at the M Chinnaswamy Stadium.
Leading the side, Sachin Baby top-scored for Kerala with a sedate 61 off 96 balls, while opener V A Jagadeesh contributed 60 off 98 deliveries.
Chasing a modest total, Jharkhand was helped by Tiwary's 94-ball knock, which was studded with seven boundaries and a six.
Kaushal Singh made a brisk 48 off 43 balls with the help of four boundaries and a six before Tiwary and Ankit Dabas guided the team past the Kerala total with three overs to spare.
Rahul Shukla was the most successful bowler for Jharkhand, returning figures of 3/47, while Aaron gave away 52 runs in his quota of 10 overs for one wicket.
