I -797B approval notice with LNU, what should be put in DS -160

Hi ,

My H1B got approved and got I -797B approval notice.As in my passport there is no Last Name so in approved petition name appears like this LNU, XXX where XXX is first Name.

From this h1 fourm i got that when there is no last name we should fill DS -160 like FNU XXX.so I am not sure how should i fill my name in DS 160 same like I 797B (LNU XXX as it will make I797 and DS-160 similar) or like FNU XXX as suggested by most of the people ???

I am in very much trouble, expecting some help from this fourm .