Keep in mind Spock states he publicly "promised to save the Romulan homeworld" (out of character for logical exact probability counting Spock to promise anything, but that's what he said). Nero would have had to know about that.Currently they think they have a year left. Picard will command the armada, but then it will suddenly be cut to hours
If the Romulan government was hiding things from Nero, Spock was not. He outright spoke of the danger and promised to save it. That Spock would go through that pretense just to destroy Romulus makes no logical sense. Especially once it would be clear years long evacuation efforts etc were done by the Federation, which Spock wouldn't hide.
Even if Nero in his anger just completely became irrational, the probability of his entire crew doing the same is unlikely. They need to come up with another justification for Nero's grievances against Spock because Picard is throwing it all out the window.