Preheat oven to 350°. In an 8" nonstick skillet over medium heat, cook bacon until crispy, 8 minutes. Drain on a paper towel-lined plate, then chop.
In a large bowl, stir together cream cheese, mayonnaise, sour cream, garlic powder, and paprika and season with salt and pepper. Fold in chopped spinach, bacon, Parmesan, and ¾ cup of mozzarella.
Transfer dip to an 8" heatproof skillet and sprinkle with remaining ¼ cup mozzarella. Bake until golden and bubbly, 25 to 30 minutes.
Serve with tortilla chips or toasted baguette, as desired.
