Melt the butter over low heat in a large heavy saucepan.
Add the sugar, water, and honey and stir constantly until melted, using a wooden spoon.
Increase the heat to moderately high and continue cooking for 15 minutes, or until the mixture reaches 290 degrees (hard-ball stage) on a candy thermometer, stirring often with a wooden spatula, scraping the bottom of the pan to make sure the mixture is not sticking.
Remove the pan from the heat and stir in the chopped nuts and vanilla extract.
Pour the toffee evenly onto the prepared baking sheet.
Cool about 5 minutes, until the surface is barely set.
Sprinkle the top of the toffee with the chocolate chips.
Let stand about 10 minutes, until the toffee is completely set and the chocolate is melted.
Spread the chocolate evenly in a thin layer over the toffee.
Cool completely until the chocolate is firm.
Break the toffee into rough pieces and store in an airtight container for up to 5 days.