Place the first 5 ingredients (pecans, brown sugar, water, butter, and salt) into a heavy sauce pan.
Cook over medium to medium high heat for about 5 minutes or until the liquid is thick and mostly coating the nuts, about 5 minutes.
Remove from heat and continue stirring for another minute or until the toffee completely coats the nuts.
Transfer the nuts to a parchment lined, heat proof surface and spread out the nuts. Careful, as the nuts are EXTREMELY HOT!
Let cool about 5 minutes (until just cool enough to handle) and then break apart any nuts that are stuck together.
In a small, shallow, microwave safe bowl, melt the chocolate chips at 30 second intervals (stirring after each 30 seconds) until the chocolate chips are completely melted.
In another small, shallow bowl add the powdered sugar.
Dip the candied nuts in the chocolate and then place on a wire rack that has been placed over a backing sheet (to catch the dripping chocolate).
Allow the chocolate to harden. You can place the trays into the refrigerator to speed up the process.
Once the chocolate has hardened, coat the chocolate covered toffee nuts in the powdered sugar.
Store in an airtight container for up to 5 days.