The leader heads to Stadio San Paolo with a 13-point lead after taking 22 wins and three draws from 25 matches this season.
Napoli has only lost once in the top flight since a 3-1 defeat to Juve in the reverse fixture in September, but three goalless draws in their last five games have seen Carlo Ancelotti's side fall further behind the champion.
Although he acknowledges it will be a difficult match, Chiellini thinks a win for Juve will prove decisive in their quest for an eighth consecutive Scudetto.
"It'll be a great game against Napoli," he said. "They've made us sweat in the last few years.
"We have to give a little thought to Atletico [Madrid in the Champions League on March 12] every day, but we'll focus on that challenge after the next matches. We want to conclude the league and show that the gap at the top is right.
"It'll be an open match compared to the last few years, because the teams have a lot of wishes to fulfil. Unfortunately, I've only won twice at the San Paolo, but that stadium and that team have always brought the best out of me.
"Ancelotti knows how to manage the atmosphere and the team better. I've always rated him, and Napoli are slowly reaping the rewards, with similar players to those [Maurizio] Sarri had.
"Even though he's managed to do great things, we're doing incredible things. A win at the San Paolo would be a definitive knockout for the Azzurri."