I believe the MB chain is made in Taiwan as well, just a higher quality. Unless I have been misinformed. I'd guess they probably label it MB because its what they use on their MB line of traps.
I have never had trouble with chain marked "foreign or economy" on traps but never used it on stakes specifically.
Never thought any trap chain was made USA but definitely agree there is a quality difference between the two most supply companies offer. I won’t use what they label as import chain. Spending the couple extra dollars for piece of mind is well worth it I feel.