Rinse the white corn thoroughly in a strainer under cool water until the water runs clear. Allow it to drain for a few minutes.
Transfer the washed corn to an instant pot or pressure cooker. Add all 5 cups of water, cover, and cook on the manual setting for 40 minutes.
While the corn cooks, hydrate the shredded coconut. In a medium bowl, combine the coconut, milk, sweetened condensed milk, sugar, cinnamon stick, cloves, vanilla bean (or vanilla extract), and nutmeg.
Once the corn has finished cooking, carefully release the pressure and open the lid.
Pour the milk and coconut mixture into the cooked corn. Switch to sauté mode (with the lid open) and cook for an additional 10-15 minutes, stirring occasionally, until the porridge thickens and the flavors meld.
Serve warm, topped with a sprinkle of cinnamon or toasted coconut if desired.