Formal:
* Rien de particulier: This is the most literal translation and is appropriate for formal situations.
* Pas grand-chose: This is slightly more informal but still polite.
Informal:
* Pas beaucoup: This is a common way to say "not much" in informal situations.
* Rien de spécial: This means "nothing special" and implies that there is nothing particularly interesting happening.
* Pas grand chose à dire: This literally translates to "not much to say" and is useful when you don't have much to report.
Examples:
* "How are you?" "Rien de particulier, merci. Et toi?" (Nothing special, thank you. And you?)
* "What's new?" "Pas grand-chose." (Not much.)
* "What did you do today?" "Pas beaucoup." (Not much.)
* "What are your plans for the weekend?" "Rien de spécial." (Nothing special.)
The best translation for "nothing much" will depend on the specific situation and the level of formality you want to convey.