Origin of chock full o nuts coffee?

I was wondering the same thing and just came across this reference in a New York Times article:

= THE MEDIA BUSINESS: ADVERTISING; Chock full o'Nuts draws on its New York ties to give its image an edge. = ====== ======
"...Chock full o'Nuts, a regional mainstay that calls itself ''New York's coffee'' because it was started in the city in the early 1930's by William Black when he converted his chain of nut shops into stores that sold a sandwich and a cup of coffee for a nickel. Always linked to its city of origin, as evidenced by its checkerboard, black-and-yellow packages evocative of the old Checker cabs..."

Archive link to entire article: