Nolan told the Evening Chronicle: "I'm very good friends with Gary Speed. He rang me and asked me if I was OK, and if I needed anything.
"He said it was a great club, and that it's got a special place in his heart.
"I've heard him talking about it in the past, and it was a no-brainer when they came in for me.
"It's a good challenge for me."
Nolan will make his Toon debut today against Sunderland and added: "I know all about the Toon Army, and I've heard all about them since I've been here. That's the only thing I've heard, how great the fans are.
"We know the atmosphere's going to be great on derby day. We just hope they can keep that going until the end of the season. I'm sure they will, because of what I've heard and seen."
He added: "This is going to be a little bit bigger than a Lancashire derby.
"There will be a lot more people there, and it's a bit more do-or-die than it is there - no disrespect. It's one I'm looking forward to. "