Chance introducing American water lily (5)
I believe the answer is:
lotus
'water lily' is the definition.
(I know that lotus is a type of water lily)
'chance introducing american' is the wordplay.
'chance' becomes 'lot' (as in drawing by lot).
'introducing' is a charade indicator (letters next to each other) (some letters go before others).
'american' becomes 'us' (abbreviation for United States).
'lot'+'us'='LOTUS'
(Other definitions for lotus that I've seen before include "Large water lily" , "Water lily - fruit inducing forgetfulness" , "Sacred flower" , "One of the lilies" , "A blooming" .)