Preheat oven to 350 degrees F.
In a large mixing bowl or stand mixer, cream together butter, peanut butter, 1 1/4 cups sugar and powdered sugar.
Add salt, baking soda and eggs and mix until combined.
Mix in flour until well combined.
Use a cookie scoop or roll dough into balls, then roll dough in remaining 1/2 cup sugar.
Place dough 2 inches apart on a baking sheet sprayed with nonstick cooking spray.
Dip the bottom of a glass into remaining sugar and press down to flatten each ball of cookie dough until 1/4" thick.
Bake 8-10 minutes, or until lightly golden brown.
Let cool completely.
Scoop Nutella into a microwave-safe bowl and microwave for 30 seconds to soften.
Spread Nutella on top of each peanut butter cookie and let cool to set up.