Rob Lyon’s men carry a two-point lead into the decider with a place in the Grand Final on the line against Belle Vue or Sheffield.
Nicholls used all his track craft gained from years of experience in a glittering career to notch 12+2 in Monday’s first leg at Wolverhampton which started in tricky conditions after an unexpected shower an hour before the meeting.
And despite the 46-44 win, Nicholls insists there’s still a job to do on home shale.
Nicholls said: “We have to be delighted with that result, but it’s only the half-way stage we know that.
“It was a great first leg performance. It’s always important to get off to a good start. They had first gate choice, and did it swing in our favour, who knows?
“They came back strong, but for us to come away with a win is awesome, but we’re certainly not taking anything for granted before the second leg!
“Wolverhampton topped the standings for a long time this season and they did that because they’re a great team and they’ll come to us fired up so we have to be on our guard.
“We have to attack the meeting from the start.”
Panthers are sweating on the fitness of Michael Palm Toft after he pulled out with a hand injury after two outings in the first leg.
With Ulrich Ostergaard already on the sidelines boss Lyon will be looking at all his options and waiting for a clear idea on Palm Toft’s chances of racing.
It’s the biggest night of the season at the East of England Arena and season tickets are valid.
Panthers owner Keith Chapman said: “It’s been a great season at Peterborough and it would be lovely to see all our fans there on Monday to try and help us to reach the final.
“It should be a great night between two top teams, the top two in the country, in my opinion.”
Tickets are available to purchase online as the quickest way to gain entry to the stadium but the cash on arrival options remains available.