Nickels are a much better bet, because you can just back up the pickup truck to the bank and store them all (good luck finding a bank who will provide all you might want).
Real Copper Pennies are better in a full blow financial apocalypse because they can be melted into useful things, nickels take more heat to work with. Plus Pennnies will be the new “base currency” as the smallest unit of measure and if they are in shortage you can exchange 4 for a nickel.
Really stocking up on any coins is a good idea for financial apocalypse.
I’ve been spending my nickels and pennies buying up a good supply of the most important metal as a hedge against a full-on economic collapse:
Lead.