Nettleton, 30, was married with two young children and had been with Las Vegas police three years, police said.
Authorities said they think the shootout resulted from a botched robbery attempt, but a Las Vegas police spokeswoman said they planned to treat the slaying as a line-of-duty death.
"His death is considered to be in the line of duty, since he pulled his weapon," Officer Barbara Morgan said.
Williams was booked in a North Las Vegas jail on multiple charges, including murder with a deadly weapon, authorities said. Marshall was being treated for non-life-threatening injuries, and will be booked in jail once he is released from the hospital, North Las Vegas police said. The 17-year-old male, who name was not released because he's a minor, was booked on the same charges and held at the juvenile detention center, police said.
It was not immediately clear whether the suspects had lawyers. Neither Williams nor Marshall immediately responded to requests for comment from The Associated Press through North Las Vegas police.
North Las Vegas police Officer Chrissie Coon said the apparent robbery attempt happened after midnight at Nettleton's home.
"He was standing in the garage with the garage door open when he was attacked by multiple suspects," Coon said. "It looks like it was an attempted robbery. There was an exchange of gunfire." Clark County Undersheriff Rod Jett told reporters the slaying appeared to be a random act.
The officer's body was borne from the home in North Las Vegas to the Clark County coroner's office in Las Vegas with a procession of police cars and motorcycles.
Coon said the officer was wearing civilian clothes after arriving home from work. She said she didn't know how many shots were fired.
Morgan said the man's family was in the house during the shooting, including his mother who was visiting for the upcoming Thanksgiving holiday.
Police said plans were being made for a funeral with full departmental honors -- the third this year for a dead Las Vegas police officer.
Last month, the department mourned the death of Officer Milburn "Millie" Beitel, 30, a former U.S. Marine and six-year Las Vegas police veteran. He died Oct. 7 in an on-duty patrol car crash. Beitel's partner, Officer David Nesheiwat, 25, was badly hurt.
An investigation found Beitel was driving 71 mph in a 45 mph zone with no lights or siren when the patrol car swerved and hit a tree and light pole.
On May 7, Officer James Manor, 28, died when his patrol car crashed into a pickup truck as he was responding to a domestic violence call. Police initially charged the 45-year-old driver of the pickup with suspicion of driving under the influence and failure to yield to an emergency vehicle.
Charges were dropped after an investigation found Manor was driving 109 mph on a city street without his emergency lights or siren before hitting the pickup truck.
Clark County Sheriff Doug Gillespie termed Manor's speed "both unsafe and unreasonable."