Place the cashews in a bowl and cover with boiling water while you prepare the other ingredients. Drain after 20 to 30 minutes.
Optional step: To enhance the flavor of the soup, place the husked ears of corn over an open flame and turn occasionally until the kernels are lightly charred, repeating with each ear.
Hold an ear of corn upright in a large bowl and shave off the kernels with a sharp knife. (If you charred the ears of corn, wait until the corn is cool enough to handle.). Repeat with the remaining ears. Place the kernels in a bowl and reserve a tablespoon or two for garnish
Select the Sauté setting on the Instant Pot and let the pot heat up for a few minutes before adding the olive oil. Once the oil is hot, add the onion. Cook until the onion is translucent, 4 to 5 minutes.
Add the garlic & jalapeños and cook for 1 minute, stirring frequently. Add the carrot and celery with a pinch each of salt and black pepper and cook for 2 minutes. Add the potatoes and cook for 2 more minutes, tossing frequently to prevent the potatoes from sticking. Select the Cancel setting.
Add the corn kernels, drained cashews, 1 teaspoon salt, black pepper to taste, bay leaves, smoked paprika, cumin, celery salt, 2 cups of the vegetable broth, the coconut milk, and nutritional yeast. Stir well to combine.
Secure the lid and set the Pressure Release to Sealing. Select the Pressure Cook setting at high pressure and set the cook time to 6 minutes.
Once the 6-minute timer has completed and beeps, allow a natural pressure release for 5 minutes and then carefully switch the Pressure Release knob from Sealing to Venting to release any remaining steam.
Open the pot and discard the bay leaves. Squeeze the juice 1/2 lime into the soup, stir, and taste for seasonings. Add more lime juice or salt and black pepper as needed. The soup will be very thick at this point, so I like to thin it out a bit with additional vegetable broth during the blending stage (see next step).
Transfer the soup in two or three batches to a high-speed blender (don’t fill the blender to capacity). Be sure to remove the center cap from the blender to vent steam, but cover the hole with a kitchen towel. Start at low speed and gradually work your way up and blend until the soup is thick and creamy. I typically add 1 additional cup of broth, but if you prefer a slightly thinner soup, add more broth. Alternatively, use an immersion blender directly in the Instant Pot to blend the soup for a few minutes until the soup is pureed and thick, thinning with the additional broth as you blend.
Transfer the puréed soup to bowls and top each each bowl with the reserved corn kernels and other garnishes as desired.