Preheat oven to 350F. Line a 9x9 baking pan with parchment paper, allowing it to hang over all sides. With an electric mixer, beat butter and brown sugar on medium speed until light and fluffy, about 3 minutes. Add vanilla and mix to combine. Reduce mixer speed to low, add flour and mix until crumbly. Dump mixture into the prepared pan and press into an even layer. Bake until edges are light golden brown, about 15 minutes.

Remove from oven, then sprinkle chopped pecans over crust, and top with shredded coconut. Pour sweetened condensed milk evenly over top, then drizzle with melted caramel sauce. Sprinkle with chocolate chips and return to oven until edges are light brown, 20 to 25 minutes.

Place pan on a wire rack to cool completely, then refrigerate for at least 30 minutes before cutting into squares. The bars can be kept at room temperature, in an airtight container, for up to 5 days.