What advice would you give aspiring CISOs who have immigrated to the US?

If you come from Europe and are a CISO who has worked in "critical infrastructure" the US will be fairly easy for you.  Otherwise I would expect the US to require harder work than other regions.

It certainly helps to have some certifications and work experience that are suitable for a CISO.  Preferably information management systems (ISMS), risk management as well as applicable ISMS audit systems such as ISO 27001, COBIT, CMMI, etc. 

The US laws and regulations will be different than in other regions of the world.  You should be aware of the NIST recommendations as well as Department of Defence regulations.

Get ready to work twice as hard as the next person to achieve the same thing, because that's reality. That forced me to become very good at my craft. You have to have the mentality that you're going to be the best that you can be, irrespective of the obstacles. Nobody's going to give you any breaks. I realize that's a horrible statement to some people, but that’s the reality you have to deal with to succeed under those circumstances. You have to be exceptionally good at the things that others may just be competent at.