He is most well known for mobilising the mob which killed Tiberius Gracchus, who was at the time attempting to stand for re-election as plebeian tribune in 133 BC.
[5] Nasica clashed with Tiberius over his agrarian reform bill, which would have redistributed public land (much of which was already occupied) to poor Roman households.
After Tiberius secured passage of the reforms with the unprecedented gambit of deposing one of his sacrosanct tribunician colleagues, it was Nasica in the Senate who apparently proposed and carried funding the commission with a nugatory grant.
Claiming that one of Tiberius' gestures indicated a request for a diadem, Nasica urged the presiding consul – Publius Mucius Scaevola – to defend the republic and kill the tyrant.
[12] After Scaevola refused, Nasica incited a mob of senators – with the phrase "anyone who wants the community secure, follow me", traditional for calling a levy of troops, – and marched on the comitia, putting the hem of his toga upon his head, customary during religious sacrifice.
[13] This was an attempt to re-enact "an ancient religious ritual killing... presumably on the grounds that [Tiberius] was trying to seize power and overthrow the existing republic".