You can use yellow chartreuse in place of green chartreuse in a pinch, but it will change the flavor profile of the Last Word cocktail. Yellow chartreuse has an ABV of 40, so it’s a touch more mild than green chartreuse which has an ABV of 55.  If you’re looking for a yellow chartreuse variation of the Last Word, try the Mon Dernier Mot. This cocktail is equal parts Cognac, yellow chartreuse, ginger liqueur, and lemon juice.