The 21-year-old was thrust into a league debut for the Latics after regular number one Scott Carson, who enjoyed a season on loan at the Valley six years ago, suffered an ankle injury during the warm-up - he later left the ground on crutches wearing a protective boot.
Nicholls' only previous appearance for the club came in August in the Capital One Cup, when Manchester City thumped five past him.
But he pulled off a string of fine saves to frustrate the Addicks in the first half, before Wigan went in search of a rare away win after the break only to be denied by the woodwork.
Nicholls showed no sign of nerves as he was tested early on, making a couple of sharp saves to deny Addicks midfielder Bradley Pritchard.
It should have been third time lucky for Pritchard on the half hour mark but he fluffed a golden opportunity to put the hosts ahead.
Cameron Stewart jinked his way to the byline and pulled the ball back for Pritchard, who had a free shot from the penalty spot but blazed it over the crossbar.
Things got worse for Charlton moments later when striker Yann Kermorgant suffered a recurrence of the ankle injury which had kept him out for the previous month and limped off.
And Nicholls pulled off a stunning save just before half-time when he clawed out Richard Wood's point-blank header from Dale Stephens' corner.
Wigan, still getting to grips with combining their Thursday night Europa League outings with a promotion bid, enjoyed plenty of early possession but too often their final ball was lacking.
Their only opportunity of note in the first half was a header from Grant Holt which he planted straight at Ben Hamer.
However, they improved vastly after the break, but not before Nicholls was beaten by a 20-yard rocket from Stephens which fortunately for the youngster flew inches wide of his right-hand post.
Charlton had a huge let-off moments later when Chris McCann met Ben Watson's corner with a powerful header which crashed off the underside of the crossbar and bounced to safety.
Hamer then saved low down from Leon Barnett and Emmerson Boyce volleyed narrowly wide from another Watson corner.
James McCarthy then blazed over from the edge of the box, Watson fired wastefully wide and Holt's goalbound shot was blocked by Wood, leaving Charlton more grateful for the point by the end.