In a large mixing bowl, beat peanut butter, powdered sugar, brown sugar, and butter until combined.
Add 3 cups crushed pretzels, beating until combined.
Line a large baking sheet with parchment paper.
Using a 1-inch cookie scoop, form dough into balls. The dough is crumbly, so press firmly into the cookie scoop so that the dough adheres. Lightly roll the truffle dough in your hands to make sure they are smooth.
Place in the freezer for at least 2-3 hours, but ideally overnight. You want them to be frozen solid.
In a medium microwave-safe bowl, heat the baking chocolate at 30-second intervals until melted and smooth.
Using a fork or toothpick, dunk the truffles into the melted chocolate, tapping off any excess.
Return to the parchment paper to set.
In a small microwave-safe bowl, heat the peanut butter chips at 30-second intervals until melted and smooth.
Drizzle the melted peanut butter chips over the truffles.
For garnish, immediately sprinkle remaining 1/4 cup crushed pretzels over the truffles.