Мы не здесь, if you want it. The "absent" subject with "нет" is always in the Genitive.
English does not have this structure. Say, you need to express the idea that someone is away. The person is not here. You have two options to think about this in Russian:
- This person is in the place called "not here". Somewhere else.
- There is no such person here. They are away.
The first interpretation gives you "Nominative" + «не здесь». The second gives you "Genitive" + «здесь нет». Which is quite idiomatic in Russian:
- Его нет. Позвоните, пожалуйста, завтра. = He is away. Please call tomorrow.
- Анны здесь нет. = Anna is not here./Anna is away.
- Меня нет дома. = I am not at home.
Obviously, the distinction is lost the moment you translate it into English, so we accept the other option, too: Он не здесь, Анна не здесь, Я не дома.
How can you even say "We aren't here"? Wouldn't it be better to say "We aren't there"? Нас нет там.