Um, it depends on what you want to hear, I guess, Macca.
Some veterinary nurses are more like basic receptionists with a bit of nursing work thrown in; others are qualified, expereinced and highly capable of doing everything, including de-sexing of the animals.
That also depends on the surgery, the location etc. For example, a country practice with only one residing vet and a vet nurse who happens to do everything is one scenario, but another practice in the big smoke with half a dozen vets and a dozen or more nurses would not consider doing anything like that!
Same as with tattooing, you have learnt that some vets do it, others don't. Some nurses do it, some don't.
So to answer your question, every practice is different, as is every nurse's level of experience and qualification.
I'm rambling, it's late...Lol. Hope that made sense.