Preheat the oven to 350 degrees. Place the chocolate and butter in a large metal bowl set over a pan of simmering water. When the chocolate is just melted, remove from the heat. Add the sugar and mix well. Add the eggs and vanilla and mix well. Add the flour, chips and pecans, and mix well. Drop by large spoonfuls onto a well-greased sheet pan. Bake 7 to 10 minutes, or just until the cookies are set. Let cool on the pan at least 5 minutes, then remove.