Home defeats to Stoke and Blackpool were caused by mistakes, not the 4-5-1 formation says the Toon skipper.
"We were brilliant at Everton and nobody moaned about playing 4-5-1 then," said Nolan. "We let sloppy goals in and suddenly the formation is being questioned. We've come unstuck because of two badly defended set-pieces.
"The formation wasn't the problem, the little mistakes at set-pieces were. That has to be a massive lesson for us because we can't afford to give away sloppy goals.
"There is a lot of disappointment around after the Stoke defeat, but if you defend set-pieces badly you'll get punished in this league."