While both make fabulous dessert cocktails, the two liqueurs are different. Creme de cacao is still a sweet chocolate liqueur, but it also shows off vanilla notes. However, Godiva chocolate liqueur incorporates loads of chocolate with a creamy base for the most luscious texture -- think liquid chocolate here. This cocktail was tested with chocolate liqueur, so that's what I recommend. But if you substitute creme de cacao, let me know how it goes!