In the bowl of a stand mixer fitted with the paddle attachment, cream the peanut butter and butter together on medium high speed until combined - about 2 minutes.
Add in the confectioners sugar on low speed until combined.
Add in the vanilla and salt and beat on high until fluffy - about 1 minute.
Fold in the chopped peanuts if using.
Roll the peanut butter mixture into balls and place them on a baking sheet lined with parchment paper for easy clean up.
Freeze the peanut butter balls until solid - about 20 minutes.
In a small microwave safe bowl, melt the chocolate and coconut oil together in 30 second increments. Stir well in between each interval.
Dip the frozen balls into the chocolate to coat them. Decorate them with sprinkles or chopped peanuts if desired.
Place the balls into the fridge until the chocolate is hardened - about 20 minutes. Serve peanut butter balls chilled.