Goretzka has less than a year to run on his existing deal with the German champion and has been touted as a possible target for Manchester United and Real Madrid.
The 26 year old scored five goals and provided the same number of assists in 24 Bundesliga games last season, while also playing a direct part in four UEFA Champions League goals.
Recently-appointed boss Nagelsmann has already stressed he is eager to keep Goretzka at Bayern, but contract talks with the midfielder are out of his hands.
"I'm not involved enough that I have a say every day. I stay out of these issues," Nagelsmann said. "Of course I have talked to him about my plans for him.
"I've told him I'd be happy if he extended and I'm also confident. There are several topics involved when it comes to discussing a contract extension.
"I'll continue to focus on the sports side of things and show him he can be one of the most dangerous midfielders in Europe. He has potential to get even better."
Goretzka is not alone in being linked with a move away from the Bavarian giant, with France international midfielder Tolisso reportedly seeking a fresh start.
But Nagelsmann has left the door open for Tolisso, who will become a free agent next year, to prove himself this season on the back of a disappointing 2020-2021 campaign.
"He is currently in isolation in France. I'm looking forward to when he returns and trains with the team," Nagelsmann said.
"His contract situation is known to everyone. I assume that when he's healthy again, he'll be part of this team."
Nagelsmann was speaking on the back of Bayern's 3-0 friendly defeat to Napoli, making it three losses and one draw in his first four games in charge.
He has had to make do without a number of players that have been away on international duty, though big-hitters Robert Lewandowski, Serge Gnabry and Goretzka returned on Sunday (AEST).
The former RB Leipzig boss is not concerned about results so far, however, and has hinted Bayern could yet strengthen before the transfer window closes.
"I said before that I'm taking over a well-functioning team," Nagelsmann added. "But I haven't had the full team yet.
"On Monday we will be complete when others return, and then it's about finding the rhythm in training"
"I'm not worried about these scores. I think the first half today was good. We had control and played well, but we didn't manage to create a lot of chances in the final third.
"The goals we conceded were annoying, but that can't really be a reference because we made a lot of changes
"Our task as a club is to always observe the market. We have a good squad, but we can always improve it. Every coach in the world wants the best possible team."
Kingsley Coman sustained a bruised rib in the loss to Napoli, but Nagelsmann confirmed at his post-match news conference that he does not expect the Frenchman to be out for long.