Preheat oven to 350 degrees F. Line baking sheet with Silpat or parchment paper.
To prepare sauce, mix together soy sauce, maple syrup, gochuagaru, and garlic powder in a small bowl and set aside.
Heat a pan over medium heat. Add walnuts and stir frequently for a minute or two. Lower heat and add sauce. Mix until well incorporated and sauce on walnuts becomes sticky, 2-3 minutes.
Spread coated walnuts evenly on prepared baking sheet. Roast for about 5-7 minutes, stirring halfway, until they become light brown. Remove from heat and cool completely.