If Pochettino have that winning mentality as a coach then transforming Chelsea won't be difficult but if he is like other coach that has work for Chelsea , even if Chelsea still bring good players not will still change. The previous coaches worked with good players but it was still not well with them. I'm believing their will be a difference in pochettino as coach because of his experience. Chelsea has really suffered, it will be too much for the club to continue with the bad performance next season.
Mauricio Pochettino has never won any Premier League titles during his time in charge of Tottenham, so I wouldn't believe he has a winning mentality other than just doing it with PSG. I think he can change Chelsea's mentality and players' confidence to do better next season, but I believe he will still be like before when he was at Tottenham.
I really wonder why Chelsea failed to find an agreement with Luis Enrique who has a better record on his coaching CV than Pochettino. Luis Enrique is a great coach who has been good enough to prove his quality with Barcelona a few seasons ago. I know the character of the game of the two coaches are both attacking, but in conclusion Luis Enrique still tends to be better in my opinion.