Melt ¾ of the chocolate chips in a double boiler, saucepan, or microwave. In a food processor or high-powered blender, combine the melted chocolate chips, tofu, peanut butter, dairy-free milk, and vanilla. Blend until very smooth, pausing to scrape down the sides. Pour the filling into the graham cracker crust and chill for 2 hours.
Melt the remaining chocolate chips with the coconut butter and drizzle over the chilled pie. If desired, add chopped nuts. Refrigerate for another hour to harden the chocolate topping or until serving.