Blend the plant milk and cashews (preferably soaked, see note) in a high-speed blender until smooth, about 40 seconds.
Combine the plant milk cashew mixture, bay leaf, and garlic powder in a large nonstick skillet or medium saucepan. Bring to a simmer over medium heat, stirring and scraping to prevent clumps.
Simmer until the sauce is smooth and slightly thickened, up to 10 minutes.
Stir in the miso, nutritional yeast, and sugar (if using) until the mixture has an even consistency.
Add the corn and stir to coat well. Continue cooking until the corn is heated through, 2-3 minutes.
Season with salt and pepper to taste. Serve immediately.