Recently, I posted a post about Poker Dice, but I had to resort to the combination [poker][dice]. Poker has nothing to do with this. Dice barely has anything to did with this. Therefore, I think that there should be a new tag for questions regarding this game. Or does one already technically exist?
Assuming that the game of Poker Dice is on-topic at all, then it is reasonable to have a tag for it. After all, it is normal to have a tag for each game.
Dice games are on-topic, according to this earlier discussion, so Poker Dice qualifies.
At your level of reputation, you can create a new tag. So you could add it to your question and see how it is received.
Incidentally, the only other question I can see that references Poker Dice (here) is tagged with just dice.
Go ahead and create the tag, that reasoning is perfectly solid.
If we do have a tag for this, it's not very discoverable to either of us. Were we to discover it later we'd probably create a synonym. We can cross that bridge when we come to it.