This promo recipe was clipped from a newspaper and found in a large collection, publish date is 1974. I believe Chip Chop Ham is similar to canned Spam. I’ve typed it below along with a scanned copy.

Serve delicious hot
CHIP-CHOP
HAWAIIAN
Sandwiches

Take a round Sandwich Bun, open and place a slice of Pineapple, then a slice of American Cheese, and a heaping amount of chip Chop Ham. Cover and wrap in aluminum foil. Place in oven at 350° for approximately 20 minutes. Serve hot, for a real delicious Sandwich treat.