Preheat oven to 350 degrees Fahrenheit. Line two baking sheets with silicone mats or Gefen Parchment Paper. Set aside.
Put oil, sugar, eggs, salt, and vanilla in the bowl of electric mixer fitted with the paddle attachment and mix until combined.
Stir together flour, baking powder, baking soda, and praline powder in a bowl.
Reduce mixer speed to low. Add flour mixture; mix until combined. Stir in hazelnuts and nougat chips.
Divide dough into six equal parts. Shape each into a long log of about eight to 10 inches long by three inches wide.
Place logs onto prepared baking sheets and bake until golden and just firm to the touch, about 35 minutes. Let cool slightly for about five minutes.
Using a long serrated knife, slice biscotti diagonally, about one inch thick.
Place biscotti back in the pan with the cut side up and return to the oven. Bake for five minutes longer, until slightly crisped. Remove from oven and cool on a cooling rack.
Chop the white chocolate and melt in a double boiler or microwave. Dip biscotti halfway into the melted chocolate; dipping on an angle will yield the prettiest results.
Place biscotti back on the rack to dry.