Put it at the end of a short setup, just after the plan or suggestion is shown, so the no closes the scene. Pair it with the Bruh sound before it for a slower build-up, or follow it with Emotional Damage when the person who suggested the plan needs a bigger reaction.
About this sound
Nounours says en fait non, French for actually no, in a dry, level voice that runs just over a second, with nothing behind it but the words themselves. It feels funny and abrupt because a settled idea is wiped out in three words, leaving a small jolt of finality that suits a quick, firm rejection.