Roast the chiles: If you have a gas stovetop, you can place the chiles directly over the flame until all of the skin is blistered. Otherwise, you can roast them on a grill or under a broiler. Just make sure they get blackened all over. After they’re charred, place the chiles on a plate to allow them to cool a bit. Use your fingers or a dampened paper towel to peel off the blistered skin. Cut them open, remove and discard the stem and seeds. Do not rinse them or else you’ll be removing some of their flavor. Roughly chop the chiles and set aside.
Melt the butter in a 5 to 6 quart heavy-bottomed pot over medium heat. Once the butter is melted, add the onions and the celery, stir to coat with the butter. Cook for 8 to 10 minutes, until the onions and celery are softened and are beginning to brown.
Add the garlic and cook for a minute more. Add the potatoes and the stock to the pot. Add the bay leaves, cumin, oregano, and salt. Increase heat and bring to a simmer. Lower heat to maintain a simmer and cook for 8-10 minutes until the potatoes are just cooked through.
Add the corn kernels to the pot and cook for 4 to 5 minutes, until cooked through. Add the chopped roasted poblanos to the pot.
Remove the bay leaves. Stir in the cashew milk. Add black pepper, more or less to taste. At this point, if you want a thicker base for your chowder, you can use an immersion blender or regular blender to purée up to a third of the soup.
To serve, squeeze a little lime on top of each bowl.