^You can't know that, and neither could Kirk. Would you entrust the survival of the entire Federation to a guess?
Lol. I assume that's a tongue in cheek comment unless you've forgotten TOS and Star Treks I, II, III, IV, V, and VI? Kirk's entire career is founded on lucky guesses!
Plus, while I'm talking about writer's choice rather than in character justification, we can also observe that:
1. Nero has more weapons and his weapons are way more powerful than Kirk's.
2. The gravity of a singularity powerful enough to prevent a ship from pulling away at maximum warp from a distance of a few thousand meters would crush and detonate a torpedo in a heartbeat, thus preventing Kirk's weapons from doing as much damage as they should.
3 Nero's own torpedoes would detonate close to his ship.
If anything, Nero's own weapons would stand a greater chance of destroying the ship than Kirk's but it's sort of moot, since the writers would have taken care of that issue if they had decided to write the ending that way. Kirk wouldn't have to guess because Nero's ship would have been obliterated by his own hatred.