Heat a tablespoon of oil in a large pot over medium heat. Sauté the diced onions until soft and translucent, about 5 minutes.
Add the minced garlic and cook for about a minute until fragrant.
Add diced sweet potatoes, vegetable broth or water, chili powder, smoked paprika, salt, and pepper to the pot. Stir well to combine.
Bring the mixture to a boil, then transfer to a pressure cooker. Seal the lid tightly.
Set the pressure cooker to high pressure and cook for 8 minutes.
Allow a natural pressure release for about 10 minutes or perform a quick release if you're in a hurry.
Open the pot and stir in the coconut milk until smooth. Use an immersion blender or a standard blender to puree until silky smooth.
Serve hot, garnished with sliced green onions.