In a large bowl, combine cream cheese and shredded cheeses with your hands or a strong, sturdy spoon. (Using your hands is really much easier, in my opinion.)
Add in the Worcestershire sauce and green onions and mix together with your hands until well incorporated, forming into a ball as you go. Cover and refrigerate for about an hour.
Add crumbled bacon and walnuts to a large plate and mix together. Place the cheese ball in the center of the plate and begin to cover the ball with the walnut and bacon pieces. I like to gather the nuts and bacon up over the sides of the ball and press gently but firmly so the pieces stay. Continue rolling the ball around and adding the nuts and bacon until the entire ball is covered.
Store covered in the refrigerator until ready to serve (up to 4 days).
Notes
Use shredded cheeses of your choice - a total of 1-½ cups. The pepper Jack does add a bit of flavor, but you can use all cheddar if you wish, or you can use more pepper Jack.