The US already has ridiculously high sentences for drug-related crimes, and it's not clear that they have had the desired effect. It's also not difficult to find judges who have been pained to pronounce such long sentences on people who are found with, say, very small amounts of drugs on them but are still receiving sentences longer than that of rapists or murderers.
Going to the ultimate sanction therefore seems like a step in the wrong direction -- or, at the very least, seems to be tackling drug problems at the wrong end of the scale.
I don't really want to suggest legalising drugs, but the idea that it should carry the death penalty is patently ridiculous, especially when as usual there's the double standard of legal (and sometimes encouraged) tobacco and alcohol "dealing".
So basically no. Hopefully Trump can address the opioid crisis but he'll need something more meaningful than this wild suggestion if he wants to do so.