Preheat oven to 350°F (177°C). Line an 8-inch or 9-inch square baking pan with parchment paper or aluminum foil. Spray generously with non-stick spray. Set aside.

Stir together graham cracker crumbs and melted butter. Mixture will be relatively crumbly. Press onto the bottom of the prepared dish and slightly up the sides.

Layer chocolate chips and next 4 ingredients, in the order listed, into prepared baking pan. Drizzle with sweetened condensed milk.

Bake for 35-38 minutes or until center is set. Allow to cool completely and lift the bars out of the pan using the edges of the parchment paper. Cut into bars.