Here's why:
* No special breed or role: Any breed of dog can be trained to be a guard dog, and their duties wouldn't change based on where they're guarding (a nursery, a house, a business, etc.).
* Focus on temperament: The most important factor for a nursery guard dog is its temperament. It needs to be reliable, calm, and non-aggressive towards children.
* Formal security roles: Guard dogs are more often used in professional security settings (like banks, factories, etc.), where they might have more specific names or designations.
Instead of a specific name, you could describe the dog's role:
* Nightwatch dog
* Nursery protector
* Guardian of the nursery
Ultimately, the best name for the dog would depend on its personality and your preference.