Napoli have a number of advantages to get the Serie A trophy back and maybe the effort will be a little more convincing after they managed to take the top position from Inter Milan again. Now what Napoli needs is to play consistently until the end of the season and must not make any small mistakes in order to maintain their chances. It is not an easy job but they can definitely get through it if they are consistent in the remaining matches for this season.
With only 2 points more than Inter Milan but with less goal difference, Napoli does not have too big advantage against Inter Milan for winning Scudetto. If Napoli lose one match, they can fall behind Inter Milan instantly, it's big risk for Napoli. Napolli are not too strong for winning all last 13 matches and Inter Milan will have some opportunities for catching and passing through Napoli in Serie A.
Inter Milan themselves will be fighting in the Champions League so their focus will definitely be divided, so this momentum can be utilized well by Napoli. However, a great effort must be made because if you make a mistake, the opportunity will be lost and Napoli must not do that.
Participation in Champions League will affect Inter Milan, but they are experienced enough to play well in Serie A while they are also fighting in Champions League. It's disadvantage for Inter Milan, but I believe they can manage this well with their proven quality and experience in latest seasons. From players to coach, Inter Milan have enough quality and experience to do it well.