That's the simplest way to do it, but not the most accurate (nor the way most equity formulas handle it).
Let's use a simple three-way chop as an example, where chip stacks are 50%, 30%, and 20% of the total chips in play, with stated payouts of $60, $30, and $10 (totaling $100).
The 'easy' way is to award $10 to each player (3rd place money), and divide the remaining $70 according to the chip stack sizes ($35, $21, and $14), making the chip chop values $45, $31, and $24 (totaling $100).
But that totally discards the probabilities of each player's chances of winning money by finishing 2nd or 3rd.. There are six possible outcomes with three players (each with a specific probability of occurring): ABC, ACB, BAC, BCA, CAB, and CBA. The correct way to calculate the equity chop is to determine the probability of each outcome, multiply it times the payouts, and sum the totals of the six outcomes. This is how equity calculators perform chops.
The actual equity chop values for the example above is $41.79 / $32.50 / $25.71, not $45 / $31 / $24 as previously stated.
Doing the quick-n-dirty will always overcompensate the chip leader, because it assumes that he is a favorite to win money at all three places, when in fact, he is only a favorite to win 1st place money. By default, he must be an underdog to win money at the other two places, because his total probability to win money at all cannot exceed 100%.