Preheat the oven to 350°. Line a 15x10x1 inch pan with foil.
With your electric mixer beat butter and sugars together. Add eggs and vanilla until incorporated.
On low speed add in your pretzels and flour, baking soda and salt. Slowly mix in your oats. Set aside 1 cup of your batter. Press remaining batter into prepared pan.
In medium saucepan combine your caramels and sweetened condensed milk over medium heat until caramels are melted and mixture is smooth. Pour caramel on oat batter. Sprinkle the cashews, chocolate chips and remaining oat batter on top. Sprinkle your coarse sea salt evenly over top.
Bake for approx. 20 minutes until top starts to golden. Remove from oven and cool on wire rack. When cool, lift bars from pan with foil and cut.