1) Line a heavy large baking sheet with parchment paper. Roll out the dough to a 18-cm-diameter round. Transfer the dough to the prepared baking sheet. Using your fingers, make indentations all over the dough. Brush the dough with butter, then bake until the crust is crisp and pale golden brown, about 20 minutes.
2) Immediately spread the chocolate-hazelnut spread over the pizza then sprinkle all the chocolate chips over. Bake just until the chocolate begins to melt, about 1 minute. Sprinkle the hazelnuts over the pizza. Cut into wedges and serve.
For the pizza dough:
1) Mix the warm water and yeast in a small bowl to blend. Let stand until the yeast dissolves, about 5 minutes. Mix the plain flour and salt in a food processor to blend. Blend in the oil.
2) With the machine running, add the yeast mixture and blend just until the dough forms. Turn the dough out onto lightly plain floured surface and knead until smooth, about 1 minute.
3) Transfer the dough to a large oiled bowl and turn the dough to coat with the oil. Cover the bowl with plastic wrap and set aside in a warm draft-free area until the dough doubles in volume, about 1 hour.
4) Punch the down dough and form into ball. The dough can be used immediately or stored airtight in the refrigerator for 1 day.