PP stalling the opponent? I mean you can defensive play with pretty much all Pokemon and just go for Toxic + recovery item in Gen 1. Admittedly I don't play nuzlocke, so I can't talk much regarding it. Articuno can still beat the Elite 4 and despite the nerf is powerful enough. But relative to Gen 1, I think it got significantly worse.^To the above guy, the Articuno part is only true if your only way of going in-game is just clicking the strongest Move. For some people that's it, but not everyone has to play the game like that.
In exchange of what it lost, Articuno in Gen 3 gained Pressure and Leftovers as item. This means that it can pull off the Sub + Protect Pressure tactic. If he is faster than the opponent (and since opponents in-game often dont have EVs, he will be) , this means Articuno wins vs almost 100% of opposing Mons by PP Stalling the moves that can break Sub. Aerodactyl is the best Mon at abussing this strategy, but Articuno has the advantage of not needing it vs Giovanni (it just OHKOs all Mons with Ice Beam) and winning faster vs Lance, Bruno's Onixes and Blue's Rhydon. Articuno also starts at level 50 vs Aerodactyl needing to be trained, so the only investment to beat the game with Articuno ends up the time needed to PP Stall, which is not much.
Sub + Protect + Pressure is a very viable strategy in Nuzlocke runs of hard Hackroms. In regular Pokemon games? It's just an autowin button.