Im guessing Nero emerges from his time travel adventure and just happens to bump into the Kelvin (similar to some others thoughts) as I kinda like the idea that killing Kirks Father as well as almost his Mother and Kirk himself was a galactic coincidence.
Likely event the Kelvin is in the wrong place at the wrong time, Nero emerges sees a ship and his first instinct is to blow it up, either to avoid detection from powers higher up or just because he can.
Likely event the Kelvin is in the wrong place at the wrong time, Nero emerges sees a ship and his first instinct is to blow it up, either to avoid detection from powers higher up or just because he can.