Mi ez? 

• mi = what
• ez = this

"Is" is missing in this kind of questions. Therefore *Mi van ez? is incorrect. 

Ez mi?

This version is also possible, There is more emphasis on ez ("this one", "this item"). We mostly say this when we are surprised (to find something unexpectedly) or there are several items and you emphasize that "this one" and not another item. 

@hunpron

#onthisday #what #whatisthis #hungary #hungarian #magyar #language #languagelearning #fyp #fypp #fyppppppppppppppppppppppp

♬ original sound - Hungarian Pronunciation