Now, Poccetino is their official coach. he should be able to fix Chelsea back to improve. at least, can compete at the top of the Premier League. because, they do not have a busy schedule like other teams. Well, the new season hasn't started yet, there's a lot of work for the new coach. his current job, releasing players who weren't part of his project. the rest, he can start to build chemistry.
You could be right because a lot of people have said that Pochettino is a coach with good experience in big teams. Chelsea can expect Pochettino to be able to bring success to his squad, especially regarding team performance. I think we all still don't know what impact Pochettino will have on Chelsea's form, but there is good hope of him next season.
Chelsea are expected to improve with Pochettino, but I believe he will not be able to win titles for Chelsea in one season. Qualification for the Champions League and European competition next season is the most likely wish, but I don't expect him to be able to rival Pep Guardiola at Manchester City.