This is the 427th most frequent Portuguese word.
chega
"Chega" means "arrives" or "enough," depending on context.
In this sentence, 'chega' is the conjugated form of the verb 'chegar' meaning 'arrives' in the third person singular (ele/ela/você).
Ele chega às oito da noite.
He arrives at eight in the evening.
Here, 'chega' is used as an interjection to express stopping or sufficiency.
Chega de desculpas!
Enough of excuses!
'Chega' is used here in conjunction with 'a ser' to express reaching a certain state or level.