Mix the praline with the nuts. Cut the puff pastry into strips and each strip into triangles, and roll each piece with a rolling pin to make it thinner.
On the longest side of each triagle, place some chopped chocolate pieces and some of the praline mixture, and roll up into a croissant shape. Place in a lightly buttered baking dish, brush with butter and bake until golden brown. Decorate with chocolate syrup and serve.