Magic Aura and Shatter

[Graysire]

Does Nystul's MAgic Aura making something seem magical make it immune to Shatter?

with Shatter "detecting for magic" finding it magical, and then not working?

[Necroticplague]

No. Shatter doesn't 'detect' magical auras. It just fails to work on magic things.

[KillianHawkeye]

Necroticplague is correct. At best, you might be able to trick someone who can see magical auras into not shattering your enspelled item.