Here's a bit of history for you...
Back in the mid 19th century, the Chinese heard about the California gold rush like everybody else. The men left in droves to go to "The Gold Mountain" which is what they called America. Once they got here they realized that gold did not litter the streets as advertized and they settled for doing manual labor and menial jobs like laundry and such.
Being men, (the women were not allowed in the country at the time) they were lousy cooks. However, what they were eating was so radically different it became popular with the non Chinese even though in China it would have been thrown out, it was so badly cooked.
Chop suey is literally left over scraps. The Chinese men would throw bits and pieces in a wok and cook it up. So, there is no difinitive chop suey recipe; it is whatever the cook wants to put in it.