Mix buttermilk and oats in large bowl. Let stand 5 minutes. Whisk in eggs.
Mix in flour, sugar, baking soda and salt; stir in chopped hazelnuts. Heat
heavy large skillet over medium-high heat. Brush with oil. Drop batter by
1/3 cupfuls into skillet, spacing apart. Cook until bubbles form on top of
pancakes, about 2 minutes. Turn and cook until bottoms are golden, about 2
minutes more. Transfer to plate. Repeat with remaining batter, brushing
skillet with oil as needed. Serve with maple syrup.