Laredo, Texas has AHB. You should plan on requeening. Dark bees may represent German black genotype, which persists at about 25% level in thoroughly Africanized areas. See fig 2H and 2I in: http://jghoneybee.com/wp-content/uploads/2012/01/Thrice-Out-of-Africa-Ancient-and-recent-expansions-of-honey-bee.pdf
In my experience, the AHB don't get really aggressive until the hives build up, so let them fill the nuc, and then requeen, (make sure that late in the season you can get a bred queen, which might be pretty difficult). Defensiveness fluctuates just like in european bloodlines, when the hive is prepping for a swarm, they are very edgy.
Don't go beyond one deep, or you get a management problem (including early swarms and drones that will affect your other hives genetics). Don't let the drones persist into the spring swarm season or you will add to the AHB issue in the area and your other hives.
Alternatively, you can let them build out, kill the (assumed) AHB queen and then combine to just add resources to your strong hive.