Yes surely there is a chance that you will get a nit in obc category with 87percentile in jee mains. 

Hey syam.

See right now it is difficult to tell u which college u will get until the NTA announces the final result as u have been provided with the percentile score in ur shift only and that too in ur slot. With this percentile u would be getting the average NITs like NIT JALANDHAR , NIT RAIPUR , NIT PATNA , NIT AGARTALA , NIT DURGAPUR. I m providing u a link for ur help.

https://www.google.com/url?sa=t&source=web&rct=j&url=https://engineering.careers360.com/jee-main-college-predictor&ved=2ahUKEwjZkMOY7s_hAhXm6XMBHbdcDiQQFjABegQIBRAB&usg=AOvVaw1pTMu5LewXe0n3JPiA8V2U

Ask if any query. Good luck