The Blues are often critiqued for holding onto a lot of young players, and sending them out on loan for multiple years.
Chalobah was expected to go out on loan this summer, but impressed Tuchel in pre-season and has not looked back.
"It's a nice development being on loan at different clubs and playing a lot of games," said Tuchel, per the club website.
"You can see that it helped him to deal with the situation here. It's impressive and I'm very happy for him.
"For him personally, I think this was the key. For another player it can be that training is more relevant. It depends on the individual situation. For Trevoh it was very important to play these matches.
"It was important to play in different countries, different competitions. This is what you see now, he can adapt."