Formal:
* 晚安 (wǎn ān) - This is the most common and polite way to say good night. It literally means "good evening" but is used as a way to say good night.
* 祝您晚安 (zhù nín wǎn ān) - This is a more formal way to say good night, using the honorific "您 (nín)" for "you." It means "I wish you a good evening."
Informal:
* 睡好 (shuì hǎo) - This means "sleep well" and is a more casual way to say good night to friends or family.
* 早点休息 (zǎo diǎn xiū xi) - This means "rest early" and is a more informal way to say good night, especially if you're suggesting someone should go to bed.
Other options:
* 好梦 (hǎo mèng) - This means "sweet dreams" and is a nice way to end a conversation.
* 明天见 (míng tiān jiàn) - This means "see you tomorrow" and is a more casual way to say good night, especially if you'll be seeing the person again soon.
Ultimately, the best way to say "have a good night" in Chinese will depend on your relationship with the person and the situation.