I had this idea before and did it as my special stream for 1k followers:
https://www.twitch.tv/videos/156422680?t=12m48s
It was a really fun idea, my chat had commands to change mario powerup/itembox (including invalid states), mario pose, toggle level water/slippery, bgmode (just to mess a lot with the game on the end)
For this I just wrote a lua script for BizHawk, read the chatlog from a text file. I made the script do savestates for each commands because some powerups may crash the game, that way I can go back if this happens
https://www.twitch.tv/videos/156422680?t=12m48s
It was a really fun idea, my chat had commands to change mario powerup/itembox (including invalid states), mario pose, toggle level water/slippery, bgmode (just to mess a lot with the game on the end)
For this I just wrote a lua script for BizHawk, read the chatlog from a text file. I made the script do savestates for each commands because some powerups may crash the game, that way I can go back if this happens