Ndah had scored the winner in the previous round against Newcastle United and he struck twice in the first half against Leicester as Wolves reached the fifth round for the first time since 1998.
In the process they also extended their impressive FA Cup record against Leicester who they have now beaten in five of their six meetings in the competition.
After Ndah had fired Wolves ahead, injury and suspension-hit Leicester were briefly on level terms when Paul Dickov struck from the spot.
But Ndah's second - taking his tally to four in the last four games - and a second-half double from Kenny Miller ended City's challenge - leaving Leicester to focus entirely on their promotion push.
Ndah gave Wolves the perfect start when he cut in from the left wing after collecting a pass from midfielder Colin Cameron.
He than raced towards the Leicester area, holding off the attentions of four City defenders, before drilling a low drive under goalkeeper Ian Walker.
But Wolves were unable to build on their dream opening and Alan Rogers and Dickov both went close to forcing Leicester back on level terms before City drew level from the spot in controversial style after 28 minutes.
Referee Mike Dean had no hesitation in pointing to the spot when Dickov went down under a challenge from Denis Irwin.
But the decision prompted a furious reaction from the Wolves players who had seen Dickov secure - and then score - the match-winning penalty when the teams met at the Walkers Stadium in the league last September.
When Dean eventually restored order, Dickov calmly slotted the ball past Matt Murray from the spot.
Wolves' anger at being pegged back once again sparked them into life and Ndah was inches away from restoring their advantage seven minutes before half time only to fire into the side-netting from an acute angle after taking the ball around Walker following another Cameron pass.
But the former Swindon Town marksman proved to be more clinical on the stroke of half time when he headed Wolves back in front.
Ndah capitalised on a well-placed free kick from Irwin that he steered past Walker at the near post.
Any hopes of another Leicester fightback were then killed off five minutes into the second half when Miller set the seal on Wolves' success.
He raced on to a pass from Shaun Newton and tucked the ball under Walker from the tightest of angles.
Scottish international Miller then set the seal on a resounding win after 71 when he was again released by Newton.
His first shot was well saved by Walker, but the former Rangers striker bundled home the rebound - taking his tally to three in two games and nine for the season.