Can we decide on one or two to stick with related to gaming? Which one would be the most suitable?
I would go with gaming. It's implied that questions on an AI site will be about AI, so there's no need to specify that in a tag. The gerund form makes it clear that gaming is something the AIs are doing.
We can add tags for specific games (like Go) if they become big topics.
the study of mathematical models of conflict and cooperation between intelligent rational decision-makers
and it's applied in other fields besides AI.
Moreover Go refers to that specific board game, which had for long been considered as the only game that humans play better than machines until the AI AlphaGo came into play. So go-game seems to be particularly for Go.
On the other hand, playing a game such as World of Warcraft or Plants vs. Zombies, I would call gaming. (not that I do it...)