Toast the almonds and pistachios at 325 degrees F for 20 minutes on a baking sheet.
Combine the sugar, corn syrup, and water in a saucepan and cook to 330 degrees F. When the sugar reaches 265 degrees F, start to heat the honey in a separate pan and bring it to a low boil.
Simultaneously, whisk the egg whites to stiff peaks with an electric mixer, being careful not to overwhisk. With the mixer still on high, gradually add the honey, pouring it down the side of the bowl. Continue to whisk. When the sugar reaches 330 degrees F, pour it over the honey meringue. Mix for 5 minutes at medium speed. Switch to the paddle and continue mixing for another 5 minutes. Using a spatula, incorporate the warm nuts. This will be sticky. Apply cooking spray to parchment lined sheet pan. Pour the nougat onto the parchment paper and flatten or spread to 3/4-inch thick with cornstarch-dusted hands or rolling pin. Rest overnight at room temperature. Cut to desired sized pieces and dip half in chocolate or drizzle chocolate over the top.
How to Temper Chocolate(From Dessert Circus, Extraordinary Desserts You Can Make At Home by Jacques Torres):
Chocolate is tempered so that after it has been melted, it retains its gloss and hardens again without becoming chalky and white (that happens when the molecules of fat separate and form on top of the chocolate). There are a variety of ways to temper.
One of the easiest ways to temper chocolate is to chop it into small pieces and then place it in the microwave for 30 seconds at a time on high power until most of the chocolate is melted. Be very careful not to overheat it. (The temperature of dark chocolate should be between 88 and 90 degrees F, slightly warmer than your bottom lip. It will retain its shape even when mostly melted. White and milk chocolates melt at a temperature approximately 2 degrees F less because of the amount of lactose they contain.) Any remaining lumps will melt in the chocolate's residual heat. Use an immersion blender or whisk to break up the lumps. Usually, chocolate begins to set, or crystallize, along the side of the bowl. As it sets, mix those crystals into the melted chocolate to temper it. A glass bowl retains heat well and keeps the chocolate tempered longer.
Another way to temper chocolate is called seeding. In this method, add small pieces of unmelted chocolate to melted chocolate. The amount of unmelted chocolate to be added depends on the temperature of the melted chocolate, but is usually 1/4 of the total amount. It is easiest to use an immersion blender for this, or a whisk.
The classic way to temper chocolate is called tabliering. Two thirds of the melted chocolate is poured onto a marble or another cold work surface. The chocolate is spread out and worked with a spatula until its temperature is approximately 81 degrees F. At this stage, it is thick and begins to set. This tempered chocolate is then added to the remaining non-tempered chocolate and mixed thoroughly until the mass has a completely uniform temperature. If the temperature is still too high, part of the chocolate is worked further on the cold surface until the correct temperature is reached. This is a lot of work, requires a lot of room, and makes a big mess.
A simple method of checking tempering, is to apply a small quantity of chocolate to a piece of paper or to the point of a knife. If the chocolate has been correctly tempered, it will harden evenly and show a good gloss within a few minutes.