We've done an excellent job nullifying Taumalolo over the last few years. Get up in his face and hold him upright in the tackle. And, as above, wear him out by running at him and making him move laterally. He is very easily tired.
But of far more importance is knowing when he will run. The Cowboys like to send a forward at the markers, get a quick tunnel-ball PTB going before the defence can get markers set, and then JT13 will run the 10 metres behind where the markers should be, build up momentum, and likely get another 10-15 metres as the tacklers try to get him from the side instead of front-on. We've been awake to this for a while now and put tactics in place to prevent it.