The Magpies currently lead the way in the division with a nine-point advantage over third-placed Huddersfield Town with 10 games of the season left to play.
Rafael Benitez's side have taken seven points from their last three games - a tough run of fixtures that saw them face promotion rivals Reading, Brighton & Hove Albion and the Terriers.
"It's about holding our nerve," Colback told The Chronicle. "We've put ourselves in a great position with two fantastic wins away and then a draw at Reading.
"We've been consistent all year round; we've had the odd slip-up, but we've always reacted and that shows the strength and the spirit we have in this team now.
"It's about keeping the consistency up now and then we'll get the points we need."
Next up for Newcastle is a home encounter with playoff-chasing Fulham on Saturday afternoon.