All four sides in the group had a point after the two opening games were both drawn but until five minutes from time Zambian progress appeared under threat, with the Super Eagles taking a 57th-minute lead through Emmanuel Emenike.
However, a highly contentious penalty, which surprised even Zambia, saw Mweene casually dink home an equaliser, with qualification from the group stage all down to the final matches on Tuesday with Burkina Faso and Ethiopia the other protagonists.
There was little to choose between the sides in the opening stages, Rainford Kalaba firing a vicious half-volley narrowly high and wide for Zambia. The midfielder then curled in a cross that was gathered by goalkeeper Vincent Enyeama, just eluding Kalaba's team-mates.
However, it was Nigeria who had the chance to take the lead when they were awarded a penalty in the 25th minute when Davis Nkausa's ill-judged challenge on Ahmed Musa saw the striker tumble to the ground. John Obi Mikel took responsibility for the spot-kick but the Chelsea man scuffed his shot and the ball hit the outside of the post and bounced to safety.
A relieved Zambia came forward, Chisamba Lungu forcing Enyeama to parry the ball for a corner from his dipping free-kick. Kalaba was heavily involved, his cross headed wide by Stophira Sunzu before they failed to take advantage of outnumbering the Nigeria defence in first half injury-time, Isaac Chansa weakly finding the keeper when he had team-mates free in front of goal.
Emenike strikes again
Shortly after the restart Nigeria broke, but Musa's shot across the keeper eluded both the net and the onrushing Emmanuel Emenike. However, the latter opened the scoring with his second goal of the the tournament 12 minutes into the second half. Mikel pounced on defensive hesitancy to find Emenike in the penalty area, he collected the ball, moved inside his marker and drilled a low shot into the corner.
Kalaba then bore down on goal but his lobbed shot was blocked by the goalkeeper with 20 minutes remaining before he turned provider, rolling the ball back to Collins Mbesuma whose finish was weak and easily gathered by Enyeama despite being unmarked in the centre of the area.
However, they were given a lifeline when the referee awarded a penalty in the 85th minute when Nosa Igiebor was adjudged to have fouled Emmanuel Mayuka. Mweene strolled forward, the epitome of calm despite the high-pressure situation, hands on hips, before casually dinking the ball into the top corner.