Melanie McGuire - who wept as she heard the verdict - was convicted of murder, desecration of a corpse, perjury and a weapons offence.
She was acquitted on two counts of hindering prosecution and falsifying evidence.
Authorities charged that she wrote anonymous letters in an attempt to thwart investigators.
During the six-week trial, prosecutors said McGuire, 34, organised William McGuire's 2004 murder using her expertise as a nurse so she could begin a new life with her lover, her boss at a fertility clinic.
The jury was told that two days before her husband was last seen alive, McGuire bought a gun and bullets that matched those found in her husband's body.
His body parts were found in matching luggage that washed ashore in Virginia in May 2004.
McGuire's lawyer, Joseph Tacopina, had argued that the petite nurse was physically incapable of killing her 1.9-metre tall, 95kg husband.
Assistant attorney-general Patricia Prezioso told jurors McGuire forged a prescription for a powerful sedative - chloral hydrate - using the name of a patient from her fertility clinic on April 28, 2004, the day her husband disappeared.
During his closing argument, Tacopina also said it also would be impossible to have carried out such a bloody crime in the couple's apartment without neighbours hearing something or without leaving behind physical evidence.
Prezioso told jurors McGuire most likely had an accomplice, but no one has been named or charged. The prosecutor acknowledged there were some unanswered questions, but said there was still "overwhelming" evidence to convict the mother of two.
The defence portrayed William McGuire as a man with gambling debts who might have been killed by a creditor.