Yes, you can change your nominee. For the same, you have to submit the 'Change in Nomination Form' at the nearest branch of the SBI Life Branch or the Central Processing Centre (mentioned below).
SBI Life Insurance Co. Ltd.
Central Processing Center
8th Level, F2 Wing, Seawoods Grand Central, Tower 2,
Sector-40, Seawoods, Nerul Node, Navi Mumbai-400 706