Continuity mistake: After getting Crittendon to turn around, Hogan grabs his hat with his right hand. When the camera looks at Hogan, he's pulling his left hand back, holding his hat.
Continuity mistake: When Hogan is by the truck, Newkirk responds to his question about packages. Crittendon has his swagger stick under his arm, then it's suddenly in front if him in his hands.
Continuity mistake: In Hogan's quarters, as he and Critendon are talking, his arms are by his sides, and suddenly crossed. As Hogan goes to get his hat off Critendon's sword, his right hand is shown, then after the angle changes, his left hand draws back with the hat, and his right comes up to grab it.
Answer: Nimrod's actual identity was never revealed in the series. It was only known that he was a British intelligence agent. Nimrod was not Colonel Klink. Hogan had only implied it was him as a ruse to get Klink returned as camp commandant, not wanting him replaced by someone more competent who would impede the Heroes war activities. The term "nimrod" is also slang for a nerdy, doofus type of person, though it's unclear why that was his code name.
raywest ★
"Nimrod" is originally a king and hero mentioned in the Tanach and taken into the Bible and the Koran. His name is often used in the sense of "stalker," "hunter," and sometimes figuratively as "womanizer" as in "hunter of women." I've never seen it used to denote a nerdy person, and although I cannot disprove that connotation, I think given his role, the traditional meaning is more likely the intended one.
Doc ★
It's widespread enough that Wikipedia has an entire section on it: https://en.wikipedia.org/wiki/Nimrod#In_popular_culture