Place peanut butter in a microwave-safe bowl. Heat for 20 to 30 seconds, until peanut butter is soft and stirrable. Add powdered sugar. Stir to combine. Refrigerate.
Place 24 candy cup molds on a cookie sheet. Add 1 cup chocolate chips and 1 tablespoon coconut oil in a microwave-safe bowl. Heat for 30 seconds, then stir. Repeat until the chocolate is melted. Use a teaspoon and add a generous teaspoon of melted chocolate to the bottom of each candy cup mold. Set aside the dish with any remaining chocolate to be used below.
Tip each candy cup mold back and forth to allow the chocolate coating to go up the sides of each cup.
Place the cookie sheet holding all 24 cups in the fridge for 15 to 20 minutes to let the chocolate harden.
Once the chocolate is firm, portion out a generous teaspoon of the peanut butter mixture and drop it in each of the 24 cups lined with chocolate. Wet the back of a spoon and use this to smooth out the peanut butter and flatten it. Return the tray to the fridge for 5 to 10 minutes.
Add remaining chocolate chips (½ cup) to the chocolate bowl used in the step above. Add remaining (½ tablespoon) coconut oil. Heat in the microwave in 20-second increments, stirring in between until the chocolate is melted.
Drizzle melted chocolate to each cup until all the peanut butter is covered. Use the back of a spoon to spread melted chocolate evenly across each cup. Once all the cups are topped with chocolate, return the tray to the fridge to allow the chocolate to harden.
Store vegan chocolate peanut butter cups in a sealed container in the fridge for up to 10 days or in the freezer for up to 2 months. If left out at room temperature, the chocolate will get soft.