Uruguay international Cavani scored a first-half brace to lead Neymar-less PSG to a 3-0 victory at the Parc des Princes on Friday.
After netting a dramatic last-gasp equaliser in PSG's draw against Marseille last week, Cavani was on the scoresheet again, putting the French giants 2-0 up inside 31 minutes.
A 52nd-minute own goal from Nice defender Dante sealed the victory and sent PSG seven points clear of reigning champions Monaco, who are due to play this weekend, and Silva heaped praise on Cavani.
"Cavani is essential to our team, he produces a lot of efforts," Silva said.
"He scored two very important goals, especially the first half as it changed the game completely. It was very important for the team.
"I think that a player like Edi should keep going like this because he is helping us a lot."
Brazilian defender Silva added: "I think it was very nice, we played very well tonight. At the start of the game we wanted to master the match and we managed to do it.
"After the first goal, it was easier as Nice wanted to play a bit more, they attacked more to equalise and they allowed us space.
"The league this year is not easy, and we had to fight until the last minute to grab a result in Marseille, and against Nice, we take the three points, that's what we wanted so we are very happy.
"We deserve the win tonight and we have to keep on like this because the group is very strong. Neymar hasn't played but [Angel] Di Maria played and he had a great game."
Cavani's opener in the third minute – a glancing header from Angel di Maria's cross – brought up PSG's 2,500th goal in Ligue 1.
He doubled the lead just past the half-hour mark, prodding past goalkeeper Walter Benitez and finishing from close range in the French capital.
"All the matches are different: against Marseille, it was more complicated because the field is different, there were many things that could be better done," Cavani told Canal+ .
"Today, we scored in the first half, which then allowed us to play calmer and close the game.
"We knew it was a tough match against Marseille but it's already of the past, we saw after that match we could all do better, intensity, aggressiveness, pressure, what we a set up today. It's good to maintain the confidence."