Place cashews in a bowl and cover with 2 cups of boiling water. Let sit for 1 hour.Drain water and transfer cashews to a high-power blender.
Add cashew milk to blender with cashews and blend for 60 to 90 seconds, until smooth. Transfer ½ cup of cashew mixture to a small bowl and whisk in corn starch.Pour remaining cashew mixture into a medium saucepan and bring to a boil over medium-high heat, whisking often to avoid burning. Right before reaching a boil, whisk in reserved corn starch mixture. Boil, whisking constantly, until thickened, about 1 minute.Remove from heat and stir in green chiles, nutritional yeast, garlic, salt, cumin, and cayenne. Taste and adjust seasonings as needed (you may want a pinch more salt or extra spice from cayenne).
Serve warm with tortilla chips, or spoon over tacos, enchiladas, or nachos.
