The Portuguese Nuno, who signed a new contract in June after guiding Forest to European football for the first time since 1995, dismissed speculation that his position could be under threat as he addressed the situation following Forest's 1-1 draw at Crystal Palace on Sunday.
On Friday, he had admitted that his relationship with the club's owner, Greek businessman Evangelos Marinakis, had deteriorated, due in part to the arrival of Forest's global head of football, Edu Gaspar.
It only fuelled speculation in the UK media that Marinakis was looking for a new manager, with reports linking the 59-year-old Postecoglou with the role.
Yet other names, including Fenerbahce's Jose Mourinho and Celtic's Brendan Rodgers, have also been reported to be targets for Marinakis. Â
Postecoglou's future has been the subject of much fascination since he was sacked by Spurs in June just 16 days after he had ended their European trophy drought by leading them to the Europa League title in Bilbao.
But after Callum Hudson-Odoi earned Forest a draw with his equaliser at Selhurst Park on Sunday, Nuno was adamant there was nothing to all the speculation that he would lose his job.
"Absolute nonsense. Absurd. This narrative, it's absurd," retorted Nuno, when asked about the reports.
Yet asked if he was confident he would still be Forest's manager when the transfer window shuts on September 1, he replied: "I cannot answer that question, but what I know is that I am working and trying to do my job the best I can.
"Of course, the situation has to be solved and we are responsible people. We can have a good conversation to create a good platform for what is more important, the team.
"We're going to have it. We must. We need to have this conversation and we will have it. This is what I think is more important than anything."
Nuno says Forest need at least three players - one goalkeeper and two fullbacks - if they are to challenge in four competitions this season, including the Europa League.
Pressed on his relationship with Marinakis and Edu, Nuno added: "The truth is we have to speak, and we will do it this week.
"This is the truth, and we will try to create a better platform moving forward. I am a responsible person.
"I have to look at my squad and see what they need. Now it is only the Premier League, then quick turnaround and it is going to be Europe and the cups.''
With agencies
