In order for some NES game to work with the Coin-Op bit of the PC10, you'd need to disassemble the ROM and re-write part of the code to even handle accepting the 'coin added' signal from the PC10, as well as logic to lockout starting the game until credits are added. Similarly you'll need to compile a new custom version of MAME to recognize the game.
This is already a non-trivial task, and if you don't already know 6502 Assembly, it's even more uphill.
You would probably have an easier time achieving a similar effect by writing some changing the "start" button input in an NES emulator to a different key, then writing an AutoHotKey script that waits for coins to be added, and then when you hit the normal start button, send the alternative button you've defined in the emulator.