Do you only have one chance to react to something? For example, if you play Display of Power but it gets Censured, can you then play a second Display of Power?

After the cancel resolves, you go back to the reaction window (though it's now the other player's turn to trigger a reaction). You can play a second Display of Power after that, because there is no Max on Display of Power and it's another card (you couldn't use a single card's reaction twice, though, even if its limit allowed you to).