Something like that requires the functionality of storing people’s points/currency and such, which nightbot doesn’t natively provide. There may be a really complicated way of doing it with nightbot, but you’re better off using another bot entirely for that, such as stream elements.
As @critscan mentionned, Nightbot doesn’t offer support for such feature.
I just wanted to add that if you wanted to use channel points as coins, this won’t be possible until Twitch provides an API endpoint to those.