PSG host the German club at the Parc des Princes having lost two of their opening three matches in Group H. Beaten 2-1 in Leipzig three weeks ago, another defeat here could push last season's Champions League runners-up to the brink of elimination in the group stage for the first time since the Qatari takeover of the club in 2011.
Mbappe missed the defeat in Germany because of a hamstring injury, but returns here looking to end a run of seven Champions League games without a goal in 2020.
Neymar is also expected to start after the world's most expensive player made his return from several weeks on the sidelines as a substitute in Friday's 3-2 defeat by Monaco in Ligue 1.
"If 'Ney' and Kylian don't score then it has a big impact on us. They are decisive boys and I hope he (Mbappe) will be able to score tomorrow," said Tuchel when asked about the form of the France striker in Europe.
Mbappe is fresh from scoring twice in the 3-2 defeat in Monaco, making him the leading scorer in Ligue 1 with nine goals from just seven appearances and taking him to 99 goals in total for PSG since signing for the club in August 2017.
"We need goals and we need him to put in a big performance, and I get the feeling he is ready. He played for France and then he scored against Monaco, so now is the time for him and 'Ney' to be decisive again," added Tuchel.
Injuries and suspensions have hampered the French champions ever since the season started and will do so again at the Parc des Princes on Tuesday.
Mauro Icardi, Julian Draxler, Idrissa Gana Gueye and Thilo Kehrer are all on the sidelines along with Spanish left-back Juan Bernat, who is recovering from a knee operation and last week told AFP he hoped to be back by "February, or mid-March".
Midfield duo Marco Verratti and Ander Herrera were on Monday rated as doubtful by PSG. Centre-back Presnel Kimpembe is suspended after being sent off in Leipzig last time out.