Miguel Britos and Edinson Cavani scored the goals for Walter Mazzarri's men in the first half and Chievo were unable to respond.
The result takes Napoli up to within a point of sixth-placed Roma, giving them a three-point cushion over Palermo, while Chievo missed the chance to pull 12 points clear of the relegation zone.
Napoli took the lead after quarter of an hour with Britos meeting a corner with a powerful header which left Stefano Sorrentino no chance in the Chievo goal.
Chievo's best chance of the first half arrived after half an hour when Sergio Pellissier's shot was saved well by Morgan de Sanctis.
Salvatore Aronica was lucky that the referee did not see him lash out with his elbow and strike Alberto Paloschi in the face as the pair jostled for the ball near the sideline in the 33rd minute.
Five minutes later, Napoli were given a penalty when Sorrentino resorted to desperate measures to prevent Cavani from scoring in open play.
The Chievo custodian had no chance of preventing Cavani from scoring from the spot either as the Uruguayan doubled Napoli's advantage.
Napoli appeared to take the foot off the accelerator in the second half and they were almost punished when Cyril Thereau went close to bringing Chievo back into the game in the 66th minute.
The miss seemed to demoralise the visitors, though, and they appeared more and more resigned to defeat as the minutes passed.
Napoli played down the clock without wasting too much energy to pick up all three points at the San Paolo for the first time since they demolished Genoa before Christmas.