The model is in employment.

this was reported two months ago

Is "modelka" the nominative case of the noun?

I translated as female model and it wasn't accepted. I know it's not smooth but it isn't wrong?

Yes, it is normal to say 'someone has work'- and it doesn't necessarily mean a one-off job and it might suggest short- time work, but it is still sensible. However, ye computer says 'No'...

the model's got work

I have a work, I have work