Preheat oven to 350 degrees F.
Spray a 9 x 9 inch pan with non-stick cooking spray.
Add butter to a mixer bowl and beat until creamy. Add sugars and beat until combined. Add egg and vanilla and continue to beat about 2 minutes.
Add flour, baking soda, and salt. Beat until well combined.
Fold in chocolate chips.
Pour half of cookie dough into prepared pan and spread evenly.
Heat dulce de leche in microwave for about 20 seconds, stir and pour over cookie dough, spreading evenly. Sprinkle with pecans.
Dollop remaining cookie dough over the top and carefully spread evenly.
Bake for 25 minutes for gooey bars (add 5 to 10 minutes for a more cookie-like base).
Allow to cool completely before slicing.