Looking at
Current Melt Value Of Coins - How Much Is Your Coin Worth?
the value of a nickel ( at this writing ) is $0.059.
Do you have some reason to believe that the value of copper ( 75% ) and
nickel ( 25% ) are going to rise substantiall faster than, say, silver or gold?
If so, knock yourself out.
If not, and you are willing to bet on metals, then why not spend $1,800 or so
on a 1-ounce gold coin instead of spending that money to buy 30,522 nickels?
Note that 30,522 nickels would only cost you $1,526, so you have to decide if
storing 336 pounds of nickels somewhere in your house is worth the ≈$275 profit.
That is a stack 195 ft tall. The most compact form would be a "cube" measuring ≈11.8 inches on a side.
( note that a cube of
solid 75% Cu & 25% Ni alloy would weigh 530 lbs. )