With a 78 percentile in JEE Main 2024, even with an SC category reservation, getting into top NITs might be challenging. However, you might have a chance at some NITs or other engineering colleges that accept lower percentiles for SC candidates.

Possible Options:

1. Lower-NITs : Some of the newer or less prominent NITs might have seats available.
   
   
2. State Engineering Colleges : Many state engineering colleges might have seats available for your percentile.
   
   
3. Private Engineering Colleges : Consider applying to reputed private institutions.

It's a good idea to keep checking the specific cutoff trends of NITs and participate in all counseling rounds to maximize your chances.