Slow Cooker Spinach and Artichoke Dip

shredded mozzarella cheese

package (8 ounce size) cream cheese, cubed, at room temperature

grated Parmesan cheese

garlic, minced

freshly ground black pepper

size) artichokes, drained and finely chopped

package (10 ounce size) rinsed fresh spinach leaves, stems removed and finely chopped

Tostada or tortilla chips