Preheat oven to 325˚F (165˚C). Line 2 muffin pans with 16 paper liners.
In a Ziploc bag, add the graham crackers. Seal and crush the crackers with a rolling pin. Measure 1 cup of crumbs to a medium bowl. Add sugar and mix to combine. Add the melted butter and mix well. Scoop 2 tablespoons of crumbs to each cupcake liner. Press the mixture firmly onto the bottom of the liner with the help of the back of a tablespoon measuring spoon. Bake in the oven for 5 minutes. Remove from oven and cool on a cooling rack.
In a small bowl, add chopped chocolate. Microwave 45 seconds on high. Stir it and microwave for another 20 seconds, stir again. If still not melted, put back in microwave and cook for another 20 seconds. Stir until smooth. Set aside and cool to room temperature.
Meanwhile, in a large mixing bowl with an electric mixer fitted with a paddle attachment, add cream cheese. Beat at medium speed until smooth and fluffy, about 3 minutes. Add cooled melted chocolate and mix well. Add 1 egg, mix on low-speed until blended. Add remaining eggs, one at a time. Add sugar, cocoa powder, Nutella, heavy cream and vanilla. Beat until just combined. Do not overmix.
Fill each cupcake liners until almost full. Bake one muffin pan at a time, for 20 – 22 minutes. The middle of the cheesecakes should be slightly wobbly. Transfer the muffin pan to cooling racks and cool completely. Repeat with the other muffin pan. Transfer cheesecakes to an airtight container and chill for at least 4 hours.
For the ganache, in a medium bowl, add chocolate.
In a small saucepan over medium heat, heat until the cream just to a simmer. Pour the cream over the chocolate. Set aside for 2 minutes before stirring until the chocolate is melted and smooth. Let it set for 15 minutes at room temperature, stirring occasionally. Scoop 1 tablespoon of ganache on top of each cheesecake. Keep the cheesecakes in an airtight container in the fridge. When ready to serve, top with fresh strawberries.