In a large bowl, beat the creamy peanut butter and softened unsalted butter together with a hand mixer until smooth.
Sift the powdered sugar over the peanut butter mixture and beat until incorporated. Add a pinch of kosher salt and the vanilla extract and mix until the dough is smooth and firm enough to roll; add a little more powdered sugar if it is too sticky.
Roll the dough into 1/2- to 1-inch balls and place them on a parchment-lined baking sheet. Freeze for 20 minutes to firm up.
While the balls freeze, melt the semi-sweet chocolate chips in a microwave-safe bowl in 20-second intervals, stirring between each, until smooth. Stir in a little vegetable or coconut oil as needed to thin the chocolate for dipping.
Using a fork or skewer, dip each frozen peanut butter ball into the melted chocolate, shake off excess, and place back on the parchment-lined tray. Add sprinkles immediately if desired.
Allow the chocolate coating to set at room temperature or return the tray to the refrigerator until firm, then serve.