Line a 9 inch baking dish with parchment paper or foil. Use a square dish for thicker bars and a 9x13 for thinner bars.
In a medium bowl, combine the crushed pretzels, confectioners sugar, melted butter, and 1 cup of the peanut butter.
Press the pretzel mixture into the lined baking dish.
Melt the chocolate chips and remaining 1/4 cup of peanut butter together. Spread the chocolate mixture on top of the pretzel mixture.
Sprinkle the top of the bars with chopped peanuts if desired.
Chill the bars for about an hour in the refrigerator. After chilling, cut into squares.