Not exactly sure what nut you are referring to. I have a Chevy D60, but guts are nearly identical. The tool to remove the wheel bearing retaining nut is a standard 1-ton hub socket. KD tools # 3246, got it from NAPA. The kingpin mounting stud on the knuckle requires a 7/8" allen key. I got mine from Grainger. Dont know of any other special size nut on the axle.
My friends got a Dodge D60, if you need a measurment of something else, let me know.