In a small saucepan over low heat, melt the peanut butter and condensed milk together and stir to combine.
Add the pretzel crumbs to a large bowl and mix in the peanut butter mixture, stirring to coat.
Press the crumb mixture into the prepared dish and bake for 15-20 minutes or until set.
Remove from the oven and sprinkle on the chocolate chips. Return to the oven for 1-2 minutes, remove, and use an off-set spatula to spread the chocolate chips evenly across the top.