De rien
This is a direct translation from French, and it's widely understood.
Here are some other ways to say "you're welcome" in Haitian Creole:
* Pa gen pwoblèm (No problem)
* Se pa anyen (It's nothing)
* Se plezi mwen (It's my pleasure)
* Wi, pa gen pwoblèm (Yes, no problem)
The best option depends on the context and your relationship with the person.