In a large pot, combine olive oil and butter over medium heat. Once butter has melted, add garlic and onion. Cook until onion is tender and almost translucent. Season with salt and pepper.
Add potatoes and chicken broth. Bring mixture to a boil, reduce heat, cover pot, and let simmer for 10-15 minutes until potatoes are fork tender. Scoop out about 2 cups of mixture and puree in a blender until smooth. Return puree back into the pot.
Add half and half, corn, and chickpeas. Return to to a boil and then reduce to a simmer. Cook on low heat for 5-10 minutes until chickpeas are warmed throughout. (If using frozen corn, heat until corn is cooked). Season with additional salt and pepper, as needed. Garnish with chopped green onions. Serve warm.