For a small cloud:
* Petit nuage: This is the most straightforward and literal translation. "Petit" means "small" and "nuage" means "cloud."
For a cute or endearing cloud:
* Petit nuage: This is still acceptable, but you can also use:
* Nuage mignon: This means "cute cloud."
* Nuage adorable: This means "adorable cloud."
The best option depends on the specific context and the tone you want to convey.