Forest are in advanced talks to bring in James McAtee (Manchester City), Omari Hutchinson (Ipswich) and Douglas Luiz (Juventus) today.
Forest have so far brought in Dan Ndoye from Bologna in a £34m move, while Brazilian duo Igor Jesus and Jair Cunha arrived from Botafogo for a combined £27m.
But Nuno concedes he's frustrated about how their market campaign has run along.
He told Sky Sports: "We are very far - very, very far - from where we should be. We are very far in terms of preparation, in terms of planning, in terms of the squad.
"So we are all very worried that in two or three days time we are playing for the Premier League, the most demanding competition in the world. And we are very far. Very, very far.
"The plans that we had didn't come through. The preparation in terms of squad was not ideal. We didn't have a chance to create the bond - and this is what I think is more important.
"Because we don't know which squad we have. We have players working here that know they're going to leave on loan. We have a major problem."