JB Weld makes PlasticWeld. I would attach the broken lug back in place with JB Weld and fill in the topside of the lug with JB Weld at a 45deg angle upwards to give it some strength for pull of the latch. Picture looks like the latch has an ear that goes over the topside of of the lug as well as below, so that may have to be cut off to make clearance for the JB Weld 45deg build out bracing.
For more strength against the upward pull of the latch and because of the upper ear, might be better to use a 90deg metal angle on topside of lug and JB Weld it in place.....