This patch celebrates the New York Chiefs' win at the 1972 season championship game held in January 1973 in New York City's Madison Square Garden. The Chiefs wore green-and-gold uniforms, hence the colors on the patch. I don't know who played against the Chiefs in the finals, but the Chiefs beat the San Francisco Bay Bombers in the semi-finals. This may have been the last world championship from the International Roller Derby League -- it folded not long after in part due to rising gas prices and transportation costs. Other derby organizations existed, but none lasted very long.
One interesting difference from modern derby: the number of games each year was vastly higher. A modern team might skate 8-12 games per year, back then a team was expected to skate 120 games during that time. The Chiefs were a busy team indeed.
Also worth noting: the Chiefs' name and logo would be viewed by many in modern derby as racist and culturally insensitive.