Line an 8"x8" pan with parchment.
Place the sugar, corn syrup, and water in a medium saucepan over medium-high heat and stir until the sugar dissolves.
Brush down the sides of the saucepan with a wet pastry brush to prevent sugar crystals from forming. (While I skipped this step and didn't have any problems, it doesn't hurt to take an extra second to do.)
Cook without stirring until the temperature on a candy thermometer reaches 260 F. While you wait for the correct temperature, proceed to prepare the rest of the recipe.
Chop the chocolate into small pieces and place it in a microwave-safe bowl. Microwave until melted, stirring after every 30 seconds to prevent overheating. Stir until completely smooth, then set aside to cool slightly.
Place the egg whites in the clean bowl of a large stand mixer fitted with the whisk attachment.
When the syrup reaches 250 F, begin to beat the egg whites on medium speed.
Once the sugar syrup reaches 260 F, remove the pan from the heat.
Turn the mixer to high speed and slowly stream in the sugar syrup down the side of the bowl.
Continue beating on high speed for about 5 minutes, until the egg whites are shiny, white, and stiff.
Turn the mixer down and add the melted chocolate, salt, and malted milk powder. Mix until well-combined and smooth.
Turn the mixer off and scrape down the sides of the bowl very well. (The nougat will have the consistency of mounting putty.)
Scrape the nougat into the prepared pan and smooth it into an even layer. Allow it to cool at room temperature until completely set, then cut into small squares to serve (or set aside to use in cupcakes).
The nougat can be stored in an airtight container at room temperature for up to a week.