In a large mixing bowl, combine the softened cream cheese, shredded mozzarella, pesto sauce, garlic powder, salt, and black pepper. Mix until well blended and creamy.
Gently fold in the chopped sun-dried tomatoes and walnuts or pecans until evenly distributed.
Place a large piece of plastic wrap on a clean surface. Spoon the cheese mixture onto the center of the plastic wrap and shape it into a log. Wrap the log tightly in the plastic wrap and twist the ends to seal.
Refrigerate the log for at least 2 hours, or until firm. This allows the flavors to meld together.
Once chilled, remove the log from the plastic wrap and roll it in additional chopped nuts if desired for added texture.
Slice into rounds and serve with crackers, bread, or fresh vegetables. Garnish with fresh basil leaves if using.