The defending Premier League champions came from behind to secure a 4-2 win against Watford at Stamford Bridge last weekend before edging to a narrow 1-0 victory at Bournemouth on Saturday evening.
Chelsea have already lost three times in the 2017-18 season so far following surprise losses to Burnley and Crystal Palace in their opening nine games.
The Blues lost 1-0 to Premier League leaders Manchester City at Stamford Bridge at the end of last month following Kevin De Bruyne’s winner.
Chelsea are hoping to retain the Premier League title for the first time since Jose Mourinho’s first spell in charge of the west London club.
Former Blues midfielder Nevin believes Conte is having to mix up his tactics after rival teams started to unravel how to compete with his 3-4-3 formation.
“Teams have been trying to work out to find where the weakness is in Chelsea’s 3-4-3 system,” Nevin told Irish radio station Newstalk.
“We haven’t seen it that often in the Premier League. That’s why they were so successful.
“eople are starting to figure out Chelsea’s tactics. Hence Antonio Conte wants to change it. He went to a 3-5-2 but there are gaps there. Teams are trying to exploit it.”
Chelsea have won the Premier League title in two of the past three seasons.
The defending champions signed six players in the summer transfer window.
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