Preheat oven to 350 degrees F (175 degrees C).
In a food processor, pulse together Nilla Wafers (5 ounce), Unsalted Peanuts (1/2 cup), and Granulated Sugar (1 tablespoon) until you have a course uniform crumb.
Drizzle in Unsalted Butter (6 tablespoon) and pulse a few times to combine.
Using eight 4-inch mini tart pans with removable bottoms, add 1/4 cup of crumb mixture to tart pan and evenly spread over the bottom and up the sides, pressing lightly to compact. Place prepared tart shells on a large baking sheet and bake for 10 minutes.
Remove and allow to cool at room temperature.
Heat Heavy Cream (3 fluid ounce) in a small sauce pan or microwave until hot. Pour over Semi-Sweet Baking Chocolate (3 ounce) allow to sit for 1-2 minutes to melt.
Add Sweetened Condensed Milk (2 tablespoon) and whisk until smooth.
Scoop 1 tablespoon of ganache into cooled tart shells and spread out evenly over the bottom. Reserve remaining ganache for drizzling. Refrigerate tart shells for 15-20 minutes to firm up ganache.
Beat Cream Cheese (3/4 cup) and Peanut Butter (1/2 cup) together until light and fluffy.
Add Powdered Confectioners Sugar (1/3 cup), Sweetened Condensed Milk (1/4 cup), and Pure Vanilla Extract (1 teaspoon). Beat until combined and smooth.
Beat Heavy Cream (1/2 cup) until stiff peaks form. Fold into peanut butter mixture.
Scoop a full 1/4 cup of filling into each tart shell, smooth out the top as desired. Chill for at least an hour.
Drizzle remaining ganache over tarts and garnish with shaved chocolate and/or chopped peanuts. You may need to warm the reserved ganache for drizzling. Simply microwave under medium power, whisking at 10-second intervals.