Ok ... I'll make an attempt.
NAFTA is/was responsible for lost jobs, and suppressed wages. Those two issues are perhaps the largest felt negative affect and result from NAFTA in the U.S. In additional the rate of illegal immigration to the U.S. accelerated after NAFTA was put into effect.
NAFTA resulted in a net increase in jobs, not a decrease. Wages weren't suppressed. They just became more competitive. High wage union jobs that were lost would have been lost anyway without NAFTA. But other jobs were saved because of modernization which lowered overall labor costs per unit of production.
NAFTA forces us to be competitive, but also opens new opportunities. Yes, the status quo took a hit. But overall, the benefits outweighed the costs.
As for illegal immigration, it has nothing at all to do with NAFTA.