The Portuguese coach was sacked as Forest manager on Tuesday morning ahead of being replaced by Ange Postecoglou.`
The Mirror says at the heart of Nuno's downfall was a clash with Forest's global football chief Edu Gaspar and his decision to lean heavily on agent Kia Joorabchian.
Before Edu's appointment, after his departure last year from Arsenal, Forest had been working closely with Portuguese agent Jorge Mendes.
But this past summer, Forest brought in Douglas Luiz from Juventus and Omari Hutchinson from Ipswich Town, both players handled by Joorabchian. Nuno's request for Fulham winger Adama Traore to be signed to replace Anthony Elanga after his sale to Newcastle United was also rejected.
Both Luiz and Hutchinson have been used sparingly by Nuno so far this season, with the latter not even registered for the Europa League.
After Nuno's public criticism of Forest's summer market campaign, insiders stated it was only a matter of time before he would be axed and replaced by club owner Evangelos Marinakis.