In a large pot or Dutch oven over medium heat, melt butter.
Add onions and cook for 3-5 minutes, or until softened. Add garlic and cook for 1 minute.
Whisk in flour and continue cooking, stirring constantly, for 1 minute.
Slowly drizzle in chicken broth and milk, whisking constantly until smooth and no flour lumps remain.
Add potatoes. Cover and simmer for 15-18 minutes, or until potatoes are fork-tender.
Add creamed corn, sweet corn, kosher salt, black pepper, crushed red pepper flakes, and smoked paprika. Stir to combine.
Carefully transfer half of the soup to a blender and blend until smooth. (Be very careful, the liquid will be hot.)
Return the blended soup to the pot. Stir to combine and cook for 3-5 more minutes, or just until heated through.
Serve hot, garnished with chives or green onions.