JEE does not consider board marks when preparing Rank list. With 60 percentile, you get a rank of about 3,50,000+. This is a very low rank so it may be difficult to get into any NITs, even with OBC reservation. As you are a Keralite, I would suggest you to go for KEAM. Since you have good marks in the board exam, it really helps in KEAM admission process.