This was a concept I've had in my head for a while regarding this duo (and I feel like I borrowed part of the idea from a fanfic somewhere… I guess).
I always imagined a scene where Nigel's and Buck's ways of working would clash drastically as they tried to bring the red squirrel to justice. At the same time, the squirrel would manage to turn the two spies against each other because of the suggestion it instilled in Buck about the crimes he could commit.
I don't know if Nigel would be that noble, but given his social class and ignoring Buck's temperament, I find it very plausible.
P.S.- Sorry for the strong language, folks.