Neuer has been in the news this week with several reports suggesting the 34-year-old, whose contract expires in the summer of 2021, will look to move on at the end of this season.
The German champions have already agreed a five-year contract with Nubel, who will move to the Allianz Arena on a free transfer at the of the 2019/2020 season.
Nubel has been tipped as a long-term successor to Neuer, who also joined Bayern from Schalke in the summer of 2011.
According to Kahn, Neuer will continue in his capacity as first choice goalkeeper next season, with Nubel serving as his understudy.
"In general, as I have shown myself, goalkeepers can of course play into old age, but maintaining a high level is a great challenge," Kahn, who retired at 38, and won the best player at the 2002 FIFA World Cup told Sport Bild.
"In Alexander Nubel, we get a highly talented goalkeeper, who has the chance to develop and learn behind Manuel Neuer. Not many have the opportunity to work with the best goalkeeper in the world every day."
Since moving to Bayern Munich nine years ago, Neuer has won seven Bundesliga titles, four DFB-Pokals, one UEFA Champions League among numerous honours while also tasting glory at international level by helping Germany to World Cup glory in 2014.
