Spurs lost back-to-back games 3-0 against Crystal Palace and Chelsea, before a devastating 3-1 loss to arch-rivals Arsenal on Sunday.
Nuno also saw his side held to a 2-2 draw to Rennes in the Europa Conference League and is desperate for his first win since August.
The former Wolves manager insisted that his players have 'total belief' in him but he has been tipped as the most likely to be shown the exit door.
Simon Jordan warned Nuno that pressure will start to mount if Tottenham fail to win their next two top-flight games against Aston Villa and Newcastle.
But the bookies have already lined up a list of names that could replace him with doubts over the 47-year-old's style play after Spurs conceded nine goals and scored just one during their last three games.
Brighton gaffer Graham Potter is among the leading contenders to succeed Nuno, with Leicester chief Brendan Rodgers also in the mix.
Eddie Howe remains a free agent after leaving Bournemouth last year and he was linked with the post before Nuno was hired in the summer.
Paris Saint-Germain boss Mauricio Pochettino has been rumoured to return to Spurs ever since he left but it would take a lot to convince the Argentine to abandon Lionel Messi, Kylian Mbappe and Neymar.
Here's the list of the top contenders in full, according to BetVictor.
The rankings
Graham Potter - 4/1
Eddie Howe - 6/1
Brendan Rodgers - 6/1
Roberto Martinez - 8/1
Mauricio Pochettino - 10/1
Simone Inzaghi - 12/1
Julen Lopetegui - 12/1
Scott Parker - 12/1
Paulo Fonseca - 14/1
Erik ten Hag - 14/1
Chris Wilder - 16/1
Ralph Hasenhuttl - 16/1
Steven Gerrard - 16/1
Arsene Wenger - 33/1
There has been plenty of criticism aimed at Nuno recently - despite the Portuguese being named Premier League Manager of the Month for August.
However, the Spurs boss doesn't seem to be feeling the pressure and just wants to focus on how he can improve things on the pitch.
He said: "I'm not worried about the judgements. What I'm worried about is how we can play better. How can we play better?
"The judgement, and the criticism, and the opinion and all of that is all part of it. And we have to deal with that, we have to deal with that.
"That doesn't interfere with the way we work, it can only distract us. I'm very simple, telling you: my focus is how can we improve, how can we improve.
"In terms of the fans, now is not the moment to ask them. Of course we need their support because the players and the team need the support of the fans.
"But it's not the moment to ask them, it's the moment to deliver. Now we have to give them, so they feel again good with the team.
"They see a team that is solid and is playing good, and things go back to normal."