Responding to a fan's question on Twitter in a clip, she said: "I think layer up the chilli.
"Use some fresh chillies, use dried chilli, use smoked dry chillies as well, and you'll get much more depth. And, I add a teeny bit of dark chocolate."
Dark chocolate is commonly added to chilli dishes in Mexico and other South American countries as it adds a richness and earthiness to the meal.
Chocolate is a key ingredient in Mexican mole sauces, so Nigella isn't breaking new ground, but the addition of something sweet may surprise some fans.
As well as sharing her favourite dinner cocktail with fans - a Negroni Sbagliato - she also dished out her store cupboard favourites that she could never live without.
Her love of Italian food was evident in her list of cupboard essentials, as she named pasta, very good olive oil, butter and tinned tomatoes.
She also said she "needed" to have canned sardines and bacon in her pantry as well.
Responding to @EwmMary's question asking what Nigella's "pantry basics" are, the TV chef replied: "I have to have lemon, garlic, ginger, tinned tomatoes, incredibly good canned sardines, obviously pasta, very good olive oil, always very good unsalted butter, Parmesan, bacon," she listed.
"I think that's really the main thrust of my basics. I need those."
Nigella answered about 25 fan questions in total, recording her response to them in clips that she shared on her Twitter feed.