Hi aspirant, since you have 68 percentile with SC category in your JEE mains exam so based on that I can say that chances for you to get into NIT is possible but in lower NIT's with branches like civil, instrumentation, metallurgy or chemical etc. Otherwise better will be for you to try for any good GFTI's as you can get core as well as CSE and IT branches over there.

For finding colleges try the college predictor tool link mentioned below;

https://engineering.careers360.com/jee-main-college-predictor?utm_source=qna&utm_medium=jee_cp

Thank You.