That engine is fairly young, and the stock bottom of a BBC is pretty darned strong. Weakest spot IMO is the knurled 3/8" rod bolts.
Put the nitrous on it. Then, next year, rebuild it, replace the rod bolts with ARP,s, stud the mains & heads with ARP's, and cam it. The 414 HP Chevy ought to survive the occasional trip to 540 on it's bottom end IMO with no issues this coming year.
If the current rod bolts are bigger than 3/8"ers, I wouldn't even replace them. If they are 7/16", those are solid, damn solid.