Yes, instant espresso works too! Just like hot chocolate, which is also an alternative, the powder form will allow for the same results. Keep in mind that espresso typically has a higher amount of caffine in it. Consider finding a recipe with alternative measurements if you are using instant espresso unless a heavier jolt of caffine is what you are after! Matcha is another alternative but just the matcha alone with the sugar and hot water will not whip successfully. For whipped matcha, you will either need to whip an egg white or 2 tablespoons of aquafaba which is the liquid that can be found in a can of chickpeas until it reaches a frothy texture. Once that frothy texture is achieved, then you would add the sugar, which you would continue to beat, then you would add the matcha powder. The consistency of this topping will not be the exact one you would get with the instant coffee, espresso, or hot chocolate but it can be used as an alternative if preferred.