Add the kernels to your slow cooker along with the diced potatoes, onions, garlic, thyme, and seasoning.
Pour in the vegetable stock and cream, add the cornstarch and stir thoroughly to combine everything.
Cover and cook on high for approximately six hours, following your appliance manufacturer's guidance. Check that the potatoes are tender and the chowder is thoroughly heated. Stir well before serving.
Finish with the lime juice and green onions, tasting and adjusting the seasoning as needed.
The result should be a rich, creamy chowder with the sweetness of fresh corn, tender potatoes and a little brightness from the lime.