Liverpool smashed their then transfer record in June to sign the Germany international from Bundesliga club Bayer Leverkusen for a guaranteed 100 million pounds ($140 million) and up to 16 million pounds in potential bonuses.
However, Wirtz has yet to register a goal or an assist in seven Premier League matches for the reigning champions.
"Even though he hasn't scored any goals, he is still the player who creates the most chances in the Premier League," Nagelsmann told Sport 1 after Germany's 4-0 home win over Luxembourg in a World Cup qualifier.
"It's not his fault if his teammates don't convert them, and the statistics don't even tell the whole story."
Wirtz joined Leverkusen from Cologne in 2020 and quickly established himself as one of Bundesliga's brightest talents, bagging 57 goals and registering 65 assists in 197 appearances for Leverkusen.
But his arrival at Anfield has coincided with Liverpool's struggles this term, with the club suffering three losses in a row.
Liverpool's record signing Alexander Isak has appeared off the pace after a curtailed pre-season, while Mohamed Salah has been unable to replicate his record-breaking form, managing five goals in his last 21 appearances for the Reds.
"Wirtz needs to get used to the league. I saw him playing with total freedom. He knows what he's capable of and how things work," Nagelsmann said.
"He hasn't always had it easy - he'll have to work hard now too."