Rule 103.2.a.3
A player’s Chosen Champion is both the specific card chosen for this slot during Deck Building and also any Champion Unit with the same name as the specific card selected for this specific slot during the course of play. Example: A player chose Jinx, Rebel as their Chosen Champion. One copy of Jinx, Rebel starts the game in their Chosen Champion zone. Any additional copies of Jinx, Rebel in their Main Deck, their hand, their trash, or on the board also count as their Chosen Champion for any game rules and effects that care about Chosen Champion status during the game.