PSG's attacking options have been stretched lately, with record goalscorer Edinson Cavani having also been sidelined.
Mbappe and Cavani have been out since they were both hurt in a 4-0 home win over Toulouse a month ago, while PSG lost its most recent league match at home to Reims without the pair.
But ahead of Thursday's (AEST) UEFA Champions League trip to Galatasaray, which Neymar will miss because of a suspension, Tuchel's squad has received a huge boost.
Asked about the combination between Neymar and Mbappe, Tuchel said: "The relationship between the two is the key for us, they can bring us a lot of possibilities.
"Mbappe has been hurt for weeks, we have to be patient, and tomorrow it's impossible for Kylian to play 90 minutes.
"We have to adapt to the situation and the opponent. Tomorrow, we will be able to play Mbappe and Icardi."
Thursday's (AEST)loss to Reims was PSG's first home defeat in Ligue 1 since May 2018, before Tuchel took charge.
"It's a good thing to play quickly after the loss," Tuchel said.
"It's always hard to find a good mood after a setback; it's the challenge tomorrow against a good team from Bordeaux, to start winning again.
"It was a lack of intensity. It was a surprise for me because I made some changes to have intensity.
"I hate to lose, it was super hard. We can do better and we'll improve."