Judge Adela Cardoza says Henry Farinas would have had to serve 33 years, but the maximum sentence possible in Nicaragua is 30.
Twenty-one other people have been found guilty of crimes including laundering money, organized crime and drug trafficking in the case. Others were sentenced to prison terms ranging from 17 to 27 years on Friday.
Prosecutors say a trafficking gang believed Farinas had betrayed it and tried to kill him as he accompanied Cabral in a vehicle after a July 2011 concert in Guatemala that Farinas organized.
They say the gang laundered more than $1 billion. Cabral was not implicated in illicit activity.