Add the softened cream cheese, cheddar cheese, ¼ cup of green olives, black olives, green onions, garlic powder, and lemon juice to a large bowl. Mix until evenly combined.
Cover the mixture and refrigerate for about 30 minutes, or until firm enough to shape.
Transfer the mixture to a piece of plastic wrap and shape it into a ball. Wrap it tightly, then refrigerate for 1 hour.
Combine the remaining ¼ cup green olives and chopped pecans in a shallow dish.
Roll the cheese ball in the olive-pecan mixture, gently pressing the coating onto the surface. Serve with crackers, pretzels, or fresh vegetables.