Line a 9×13-inch baking dish with parchment paper or a silicone mat. Gather and measure your ingredients.

In a heavy-bottomed saucepan, combine unsalted butter, granulated sugar, salt, and water. Stir constantly over medium heat until it turns deep golden brown (about 10-15 minutes).

Carefully pour the toffee onto the prepared baking sheet and spread evenly. Let it sit for 1-2 minutes until it firms up slightly.

Sprinkle chocolate chips over the warm toffee, allow them to melt for about 2 minutes, then spread evenly.

Sprinkle chopped nuts over the melted chocolate, pressing them in gently to adhere.

Cool the toffee at room temperature for 2 hours or refrigerate for 30 minutes until hardened.