Chop nuts and place in a jar with a lid. Cover with about 1 ½ cups of bourbon and let soak overnight. Drain the bourbon and throw it away, it will not be drinkable.
Add soft butter to the bowl of a stand mixture and beat until creamy, 1-2 minutes. Gradually add powdered sugar 1 cup at a time and mix until it is creamy before adding more. Continue to mix until all of the powdered sugar is incorporated and large chunks form, about 3-5 minutes.
Add 1 tablespoon of bourbon, mix until combined. Drain the pecans and add, mixing to combine.
Use a 1 tablespoon scoop to form balls. Roll between your ands to form into balls and place on a baking sheet lined with parchment paper. Cover with plastic wrap and refrigerate for about 30 minutes until firm to the touch. If you need to refrigerate longer, let them warm up just a little before dipping. If they are too cold the chocolate will harden too quickly.
In a small microwaveable bowl, break up 4 ounces of chocolate into pieces and microwave on medium high for 1-2 minutes until smooth. Quickly add a bourbon ball, moving it around with a fork until it’s covered. Scoop it up with a fork and let the extra chocolate drip off. Place on the parchment paper and slide it off the fork with a knife or offset spatula. Add a pecan half to the top right away before the chocolate sets.
Once the chocolate has run out, repeat with additional chocolate.
Let sit on the counter until the chocolate has set. Use a sharp knife to remove any excess chocolate from the bottom and refrigerate until firm.