i got 90 percentile, and i belong to sc will i get a good nit college..

With 90 percentile in Jee, your expected rank would be around 86000. Now if the number of candidates in April Session increases up to 12,00,000, your rank would also increase. There are very less chances of getting into any NITs. To get a good NIT, a SC candidate must score at least 95 percentile. Based on your rank and previous year cutoff, you can expect NorthEast NITs. But chances are very low though we can't predict the cutoffs.
You can check the last year's cutoffs for all the NITs-
http://engineering.careers360.com/articles/nits-cutoff-for-top-btech-branches

YES OF COURSE ......BUT HARDER TO MAKE IT TO IITS ....GOOD LUCK DEAR