The reigning French champion will be looking to pick up a fifth win in a row when it makes the trip to Stade des Costieres on its return to action after a two-week break.
However, Tuchel confirmed at his pre-match news conference on Friday that a number of players are either definitely out of the match or are major doubts.
Marquinhos, Marco Verratti, Julian Draxler, Thilo Kehrer, Juan Bernat and Mauro Icardi are injured, Angel Di Maria and Layvin Kurzawa are banned, while Ander Herrera has contracted COVID-19.
Meanwhile, new signing Danilo Pereira and Colin Dagba have been in close contact with players who have tested positive for coronavirus and must undergo another test on Thursday.
There are also question marks over the fitness of Neymar and Kylian Mbappe on the back of a stacked international fixture list, which is a cause for concern for Tuchel, especially with Manchester United to come in the Champions League next Tuesday.
"Draxler, Verratti and Marquinhos will not play against Nimes and are doubtful to face Manchester [in the Champions League]," Tuchel said.
"Herrera has been infected with COVID-19. Danilo has been in contact with Cristiano Ronaldo, so he cannot be with us.
"Dagba was also in contact with Maxence Caqueret with the Under-21s - we will see today if he is still negative on the test so that he returns to the group.
"Kehrer is still injured and will be absent for a few weeks. Bernat is also absent and finally Icardi was injured in training last Wednesday in the inner ligament of the knee.
"It's not a big deal, but he won't be with us against Nimes and against Manchester United.
"We need an ambitious and courageous team for tomorrow. We want to attack and not take goals. We want to be ready for Manchester United.
"On the other side, we must be careful for those who have just returned from the international break like Mbappe and Neymar. Maybe we will only have 11, 12 or 13 players.
"It will be a headache tomorrow but we want to push the team to win before facing Manchester United."
Tuchel criticised PSG for a lack of transfer activity prior to the signings of Danilo, Moise Keane and Rafinha late in the window.
Sporting director Leonardo did not take kindly to Tuchel's comments and invited the German coach to leave the club if he is not happy with his financial backing.
Speaking for the first time since Leonardo's interview, Tuchel said: "I clearly heard it. I've given my opinion. In football I never take things personally.
"We have not had any contact since. I've been working with the players for two weeks - that's what I like the most.
"As a group we are all very close. But conflicts can happen. We've given our views and I don't take anything personally. I'm here to fight for what is best for the team. Now we move on."