In mixer bowl beat peanut butter and butter together until smooth.
Mix in powdered sugar and vanilla and blend on low until combined then on high until fluffy.
Place mixture into a piping bag with a large round tip.
Place half the pretzels on a parchment lined baking sheet(s)
Pipe a tablespoons or so filling onto each pretzel, then take additional pretzels and sandwich them together.
Melt 1 cup chocolate chips with 1 teaspoon coconut oil and mix until melted and smooth at 30-second intervals in a microwave.
Dip half of the pretzel sandwiches into chocolate and place back onto the baking sheet and then [lace the try in the refrigerator for the chocolate to set up about 10 minutes.
Notes
Beat the mixture on high until really creamy and whipped. Add a tablespoon of milk or heavy cream if needed. I didn't need to add any.