Spray a slow cooker insert with nonstick cooking spray.
Add the chopped potatoes, broth, salt, pepper, and garlic powder to the slow cooker. Mix until well combined.
Break the cream cheese into 4-5 pieces and place on top of the potatoes. Repeat with the 4 tablespoons of butter.
Place the lid on your slow cooker and cook on low for 5 hours, stirring occasionally.
When the potatoes fall apart to the touch and are fork-tender, uncover the slow cooker and stir the ingredients together.
Add the Greek yogurt (or sour cream) to the slow cooker and stir again until combined.
Use a hand mixer, immersion blender, or potato masher to mash the potatoes until they have a thick and creamy consistency. Feel free to leave them chunkier if that's your jam, but make sure not to over mix!
Serve immediately and garnish with your favorite toppings including fresh herbs, butter, salt, pepper, or chives.