Nenshi went to Twitter to ask for ideas on what he should wager, given that he's not a big fan of salmon and Robertson doesn't like beef.
It's been decided that the losing mayor will wear the winning city's jersey and donate just over two kilograms of food to the local food bank for every goal scored.
The loser must also recite a short poem about the victor's city.
It's the first time the Flames have made it to the playoffs since Nenshi took office and he says he wants to make the most of it.
He says he has been working on a number of poems he will expect Robertson to recite.
"I will share with you my first of many poems I think I will come up with in the haiku form," Nenshi said Wednesday.
"The brothers Sedin/Lululemon underwear/Not good for hockey."
Nenshi said Calgary has traditionally made it to the Stanley Cup the "hardest way possible" but he expects an easier road this time with a series victory in five games.