I think unless it is a well know MBA, it won't be too powerful.
However, it will still count - you will get credit when applying for a job, just won't get any recognition of a value (think of it as a checkmark rather than a plus).
However, if all of your experience is in Greece (worked for a local company, not Nestle or Coca Cola, school, etc), it will be really tough to find a job in the US; US employers prefer to hire from companies they know and familiar with. They prefer someone else to do the vetting and training.
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