Pour the peanut butter to a medium-sized mixing bowl.
Add the sugar and water to a small sauce pan and place it over medium-high heat. Let the mixture simmer for a few minutes, and once the sugar is completely dissolved, remove the pan from the heat. Let it cool for about 5 minutes.
Gradually pour the sugar into the peanut butter, stirring almost constantly, until it's a smooth, even consistency. Set aside to cool for about 30 minutes.
Once the peanut butter mixture has cooled, fold in the mini chocolate chips or chunks.
Lay a piece of plastic wrap directly on top of the surface and press it down gently. Then refrigerate until it's solid, about 2 hours.
Line two baking sheets with parchment paper. Set aside.
Use a 1-¼-inch cookie scoop to shape the truffles, placing them on the parchment-lined baking sheet as you go. They'll be round on top and flat on the bottom. For a rounder truffle, let them sit at room temperature for about 30 minutes, then carefully roll each one between your hands. Do this carefully so they don't crumble, as these are candy bar-like truffles, not super creamy truffles.
Once they're shaped to your liking, cover the baking sheet with plastic wrap and place it in the refrigerator for 30 minutes.
In a double boiler, melt the 12-ounces of chocolate -- or you can melt it in a glass bowl or beaker in the microwave, in 30 second intervals.
Remove the cold truffles from the refrigerator, and use a fork to dip each truffle into the melted chocolate to coat them evenly, placing them on the other parchment-lined baking sheet as you go. Use a small knife to help you remove the coated truffles from the fork.
While they are still wet, sprinkle them with the peanuts. You should do this after every five or so are coated, and if at any point the chocolate is becoming too thick to easily coat the truffles, heat it again, just until it's thinner.)
The truffles will set at room temperature, and are best left out of the refrigerator at this point.
Once set, you can put each truffle into a cute paper cup.