Antonio Conte's side appear on course to winning the top-flight trophy after their 2-1 win away to Stoke on Saturday ensured the Blues kept their 10-point lead over second-placed Tottenham in tact.
Chelsea conceded nine times in their opening six league games - three of which came against Arsenal at the Emirates Stadium - before a change in formation to a 3-4-3 saw Conte's men concede just four goals in their next 13 matches.
Chelsea have had a harder time keeping out the goals since January, but their attacking quality means they have still lost just once in the Premier League since the start of the year.
And Nevin believes it is Chelsea's increased solidity in defence since the switch in set-up why, in his mind, the Blues will win the title this season over their rivals.
Writing in his column on Chelsea's website, Nevin said: "One of the biggest clichés in the game is that you do not win titles without a rock-solid defence.
"That of course makes you immediately consider Man City’s back line and Pep’s ultra-positive attack-minded play. Personally I love it, even if to use a Jose line, ‘6-6 in their last Champions League tie against Monaco was not a football result but a hockey score’.
"In reality though, unless you are as good as Barcelona at their very best then many would say defensive consideration is probably a good idea in the end if you want to win the big prizes.
"Which brings us back to why everyone thinks Chelsea are unlikely to fold - the defence is infuriatingly solid if you are trying to break them down.
"Collapses tend to happen to sides that are a bit flaky, that play on the edge and are completely different one week to the next in style and in quality.
"The standard from Chelsea, primarily at the back and in defensive midfield, has remained granite-like since the infamous Emirates first half."