Lol, no it's no different. I've had many successful broody chickens hatching duck eggs. Don't interfere! (hard not to, I know).
She won't smother them. She will feel them hatching and sit tight keeping that humidity just perfect.
The only difference I found, besides the incubation length, is...
Leave mama duck to it. She knows best. Don't lift her off or interfere. You can hold a cup of water in front of her face for her to drink, and you can place a small dish of food in front of her after that for sustenance. But she needs to sit tight on that nest creating the perfect temperature...