Lalzofolai, Zico and Ronald scored for Mizoram in the Group A match which was locked goal-less at half-time. Nasaruddin pulled one back for Kerala, who were also the runners-up in the last edition.
In another Group A fixture, Maharashtra got the better of Uttarakhand in a tightly-contested match.
Allan Dias (37th minute), Mohammed Shabaz (43rd) and Santosh Koli (88th) scored for Maharashtra.
For Uttarakhand, Ashok Singh (19th) and Sher Singh (68th) found the target.
Group A has defending champions Services, last year's runners-up Kerala, Maharashtra, Mizoram and Uttarakhand. Group B consists of 31-time champions West Bengal, Punjab, Railways, Goa and Tamil Nadu.
The final is slated to take place on March 9 at the same venue.