Nigel is the name you give a pet when you want people to do a double-take. Dignified, British-sounding, slightly absurd on a golden retriever — it works precisely because of that tension.
The Posh-Pet Aesthetic
A wave of owners in the last decade has leaned into giving dogs very formal human names. Nigel fits squarely in that tradition, alongside Walter, Graham, and Porter. The comedy is built in: a muddy corgi named Nigel has a certain energy that Fluffy simply cannot achieve. It plays especially well on corgis for obvious reasons.
Pop-Culture Anchor
Nigel appears in Pixar's Finding Nemo as the helpful pelican, which gave the name a friendly association for a generation of parents who are now old enough to be naming pets. It's not the primary reason people choose it, but it doesn't hurt. The human name Nigel is Old Welsh in origin, derived from the Latin Nigellus, meaning "dark" or "black."
The Counterargument
Nigel is undeniably a bit of a joke name, which is fine if that's the intention — but it's worth being honest about that. If you're looking for something that reads as formal without the inherent wink, Crosby or Porter might serve better. Nigel commits to the bit.