Line a 9 by 9-inch baking pan with a sheet of parchment paper and dust lightly with cornstarch. In a stand mixer with a whisk attachment, beat the egg whites on high speed, just until soft peaks form.
In a medium saucepan add the honey and cook over medium heat until it comes to a boil. Remove the pan from the heat and with the mixer on low add the honey to the egg whites. Increase the mixer to high speed until the mixture has formed stiff peaks.
In another medium saucepan, add the blue agave and salt. Cook over medium heat, stirring occasionally, until it reaches a boil. Continue cooking until the mixture reaches 300 degrees F or the "hard crack stage" on a candy thermometer. With the mixer on low speed, slowly pour the hot agave syrup into the egg white and honey mixture. Mix until stiff and glossy, about 5 minutes. Mix in the vanilla extract and butter. The mixture may appear to separate but continue whipping and it with reincorporate.
Remove the mixing bowl from the mixer and stir in 3/4 cup of the dried corn. Spread the mixture evenly into the parchment-lined baking pan and sprinkle the top with remaining dried sweet corn. Let the nougat sit overnight.
Cut the nougat into 1-inch pieces with a well-oiled knife and wrap in waxed paper until ready to serve.