Nimrit is obsessed with her because what angle is left for her if we Remove Priyanka's rivalry angle from this picture..she has no showmance angle, she has no 'bff' angle.. n since she has taunted Priyanka for getting into others fight so she herself cannot do that ...but when She will not into others fight there is very low possibility of generating rivalry with other contestants...
In one line, she has nothing to offer except 'priyanka's rivalry ' that's why she is obsessed with Priyanka
While Priyanka n shiv have others angle to show... Priyanka has love angle, friendship angle, rivalry angle with shiv n stan ...shiv has that group angle, rivalry with Priyanka n shalin...