Drain and roughly chop artichoke hearts. Thaw spinach (in the microwave for 30 seconds), then press out as much moisture as possible.
Add cream cheese, yogurt, parmesan, and mozzarella to a large pot. Heat over medium until the cheese has melted, stirring often.
Stir in artichoke hearts, spinach, and garlic. For a spicier dip, optionally add drained green chiles. Taste and add salt and pepper, as needed to suit your taste. Continue cooking until mixture is hot, about 5 minutes.
