Hmmm... Beast energy is really good... but only getting one in your deck isn't the best. I wish it was just a colorless + damage bonus and then not a Prism Star. I think that would've been much better. Naganadel-GX is interesting... unfortunately I don't think it's good enough. 120 for (c) sounds good but chances are you won't have a full UB bench. You're going to want either your Oranguru or Octillery, then there's Tapu Lele... At best you're probably doing 80-100 damage, + choice band, which to be fair is still not bad, but it IS a stage 1. It's GX attack is amazing late game. If you're behind and your opponent is about to draw their last prize this is a pretty great hail marry. It also could be used early game if you're ahead and you want to bet on winning a three prize race with a superior board.