noun
A favorable moment or opening to do something; often implies a limited-time opportunity. Used in everyday speech.
今がチャンスだ。
Now is the chance.
彼はそのチャンスを逃した。
He missed that opportunity.
機会 is a more formal or written word for 'opportunity', while チャンス is casual and often implies a lucky break.
Borrowed from English 'chance'.