For Nash, it is welcome restbite after falling out with Preston boss Paul Simpson after he openly criticised team-mates and requested a transfer after Fulham had an offer rejected.
Nash will now compete with Chris Kirkland and Mike Pollitt, who signed a one-year extension, for the number one shirt, and is delighted to get another go in the Premiership.
""I'm delighted to be in the Premier League again, and when I heard about Wigan's interest I really didn't have any other club in mind.
"I enjoyed my time here last season and can't wait to start."
His new manager said: "Carlo is a top class keeper and I'm delighted he's decided to join us.
"We got to know him as a person last season, which is always very important, and I think he will fit in here."