Are all verbs meaning 'there is/there are' used with nominative in greek?

Question

I know you do use it with nominative after υπάρχει (as in υπάρχει ένας σκύλος εδώ) and the same works for είναι, but how should I use έχει?

Answer 1

All verbs which mean “there is” in Greek, go with nominative case.  Actually this nominative is their subject.  

Example:
Υπάρχει Θεός. (There is God).
Είναι κανείς εδώ; (Is there anybody here?)
Γίνεται πανικός. (There is panic.)

Which other verbs go with nominative?

The verbs είμαι (I am),  γίνομαι  (become), φαίνομαι (I seem to be),  ονομάζομαι (I am called/my name is), θεωρούμαι (I am regarded as), εκλέγομαι (I am voted), διορίζομαι (I am  appointed) and others with similar meaning, also go with nominative case.

Example:
Ο κύριος Κώστας είναι διευθυντής. (Mr Kostas is director)
Ο Γιάννης θεωρείται έξυπνος. (Giannis is considered to be clever)
Ο αδερφός μου εκλέγεται δήμαρχος. (My brother is elected mayor)

This nominative gives a property to the subject and it is called predicate. It should not be confused with the object.