The Chansey here, illustrated by Koichi Oyama, looks like a test product that was made in the early days of the Pokmon TCG
One creature in particular from that set, Monastery Swiftspear, was reprinted for Standard and remains such a potent card that she sees play in Modern burn decks
Furthermore, Gardevoir ex can place damage counters on Pokmon that can be moved with Munkidori
What affects the value of Nidoking BREAK
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When the triggered ability resolves, first the player whose turn it is (if it isn't your turn) chooses which creature they will sacrifice, then each other player in turn order does the same, then all chosen creatures are sacrificed at the same time