Preheat oven to 350 degrees.
Lightly grease 9x13 baking dish or line with parchment paper.
Cream butter and sugar together.
Beat in flour and salt until nice and crumbly.
Press 1 3/4 cups crumb mixture onto bottom of baking dish.
Bake for 10-12 minutes or until golden brown.
Stir nuts into reserved crumb mixture. Set aside.
Combine sweetened condensed milk and bittersweet chips in a microwave safe dish and heat on medium heat, in 30 second intervals in microwave until chips are melted. Stir until smooth.
Pour over hot crust and spread until even.
Sprinkle reserved crumb mixture over chocolate mixture.
Drop teaspoonfuls of preserves on top of crumb mixture.
Sprinkle with 1 cup semi-sweet chocolate chips.
Bake for an additional 25-30 minutes or until set.
Cool and cut into bars.