Brendan Rodgers was officially unveiled as Celtic manager on Friday - signing a three-year deal.
And Rodgers vowed he'll remain at Celtic for the duration of his deal - unless he's "emptied" before then.
The contract for Rodgers signalled a tweak in usual Celtic manager deal protocols with previous bosses on one-year rolling deals.
It means there is an increased commitment from both Rodgers and the board in the latest appointment.
Celtic chief executive was quizzed on the contract length and revealed the longer deal comes after "mutual excitement" from Rodgers and the Parkhead board.
He explained: “When Chris and I met with Brendan it was clear there was a mutual excitement at what we could go on to do.
"This is a mutual statement of our commitment to that. So that was an important part of it, yes.”
Rodgers said of his three-year deal: “Listen I've signed for three years.
“I guarantee I'll be here for three years unless I get emptied before that, as they say up here!
“That will be the plan and, like I say, then we can look at it from there.”
On the ambition for Celtic going forward - with Rodgers keen to make strides in Europe - Nicholson added: “From our perspective the strategy has always been clear and that’s to be a world class football club in whatever we do.
“We want to dominate in Scotland, we want to compete in the Champions League and that’s been clearly stated for many, many years. So there is no change in that regard.
"What we have done is to try and continuously improve as a football club and to invest.
"We have got a sustainable model, a self-financing model so we invest when we can for today, tomorrow and for the long-term. We all want the same thing, which is to win.”
