You seem to be missing the point I made. Nidoking makes 50/50s for the Steel matchup while running Stealth Rocks Nidoking which frees up a move slot on Nihilego so it can run extra coverage which would be either Sludge Wave or Grass Knot. Another point is that Nidoking OHKO Heatran on a switch once Air Balloon is popped while Salazzle will get worn down by hazards and outpaced by z happy hour jirachi and Choice Scarf ExcadrilI, which Salazzle cannot KO even if it Flamethrower on the predicted switch to these unlike Nidoking which can OHKO both without risking getting swept by the both of them. I am questioning your metagame knowledge because Metronome is not a set of Nihilego nor is Focus Sash Nidoking. if anything Nihilego would be running cool Electric Z set that has seen use in tours that is eved to get a Speed Boost every time a Pokemon dies which greatly helps the Flying matchup as Gliscor gets annoying. Plus Choice Scarf Nihilego vs bulk Flying is easy to take care as Gliscor, Celesteela and Mantine can come in to take most of Nihilego's attacks or when it is locked into Stealth Rock while slowly wearing it down with setting Flying setting down their own Stealth Rock / Leech Seed. Another flaw in your point is vs Mega Steelix, as it will always have Rest, so Toxic will not be able to stay and can easily pp stall out Salazzle since Mega Steelix can just click Rest till it wakes up and repeat the cycle again and again. Nidoking is also a lot better in this matchup as Earth Power helps with Mega Steelix and can threaten other Ground-types like Garchomp and Landorus. Mega Venusaur is easily taken care of by Mega Steelix and Steelium Z Excadrill after it Swords Dance once and Crobat is threaten by Mamoswine that makes 50/50s, if Mega Venusaur is too low to you kinda have to hope it does not Icicle Crash as it will make it unwinnable for Poison to win with Crobat dead. I said Electric in my first post because of newer sets like Fly Z Zeraoa and LO Raichu are being used which can sweep Poison if you are not careful, and it is easy to get them on the switch with Nidoking once Rotom-W is taken care of. This brings me back to what I said in my first post, Salazzle is really only good in mirrors and the Steel matchup, as it is Salazzles niche just like the other B ranks have the same flaw with only tilting one or two matchups into your favor.
Nidoking makes 50/50's in a different way than Salazzle does. Nothing on Steel except Heatran wants to take the Flamethrower from Salazzle and Heatran gets hit with Toxic on the Switch in, putting their only fire immunity on a timer. This is a simple case of Hyper Offense Vs Stall. Nidoking destroys Steel with raw coverage and offensives, Salazzle picks at Steel's newfound weakness in Toxic+Fire STAB, something you couldn't do otherwise. I'm not trying to knock Nidoking's Viability, I accept it is A tier for many of the reasons you suggest. However I can point to Salazzle and say it performs a similar role against Steel and Poison mirrors that Nidoking does, both of which are extremely annoying matchups for Poison as a whole.
Secondly, since when does Nidoking beat Choice Scarf Excadrill besides a switch in? Since when does it beat Z Happy Hour Jirachi again, besides catching it on the switch in? Both Excadrill and Jirachi are faster than Nidoking and force it out due to being able to OHKO Nidoking anyhow. Salazzle Choice locks Excadrill with Substitute/Protect forcing the appropriate switch while Nidoking lacks the speed to do anything to either one unless you are running Scarf Nidoking, and this is assuming neither one has any form of speed control (and they both do.). In fact Jirachi can set up
in Nidoking's face and live the Earth Power, while with rocks its a roll in Jirachi's Favor.
252 Atk Mold Breaker Excadrill Earthquake vs. 0 HP / 4 Def Nidoking: 416-492 (137.2 - 162.3%) -- guaranteed OHKO
252 SpA Jirachi Psychic vs. 0 HP / 0 SpD Nidoking: 312-368 (102.9 - 121.4%) -- guaranteed OHKO
252 SpA Life Orb Sheer Force Nidoking Earth Power vs. +1 0 HP / 0- SpD Jirachi: 281-330 (82.4 - 96.7%) -- guaranteed 2HKO
252 SpA Life Orb Sheer Force Nidoking Earth Power vs. +1 0 HP / 0- SpD Jirachi: 281-330 (82.4 - 96.7%) -- 25% chance to OHKO after Stealth Rock
Nihilego being the carrier of Stealth Rocks for Poison isn't a problem if you opt for something like Metronome Nihilego, which can actually take on and whittle down things like Mantine after a few Power Gems, which it cannot outpace with Roost or Scald thanks to metronomes damage boosting effect over multiple uses and chipping Celesteela isnt strictly a hard thing to do with careful play. Gliscor barely takes HP Ice as it stands and 2-3 power gems are all you need to get it into KO range if you attempt to switch it into the attack. Even if you decide to throw Mantine away for a scald unless a burn occurs Dragonite cant even KO Nihilego.
Vs Mantine:
1. 176 SpA Nihilego Power Gem vs. 252 HP / 160+ SpD Mantine: 150-176 (40.1 - 47%) -- guaranteed 3HKO after Leftovers recovery
2. 176 SpA Metronome Nihilego Power Gem vs. 252 HP / 160+ SpD Mantine: 165-194 (44.1 - 51.8%) -- not a KO
3. 176 SpA Metronome Nihilego Power Gem vs. 252 HP / 160+ SpD Mantine: 198-233 (52.9 - 62.2%) -- not a KO
4. 176 SpA Metronome Nihilego Power Gem vs. 252 HP / 160+ SpD Mantine: 257-303 (68.7 - 81%) -- not a KO
5. 176 SpA Metronome Nihilego Power Gem vs. 252 HP / 160+ SpD Mantine: 360-424 (96.2 - 113.3%) -- 75% chance to 1HKO after Leftovers recovery
0 SpA Mantine Scald vs. 80 HP / 0 SpD Nihilego: 116-138 (30.6 - 36.4%) -- 45.7% chance to 3HKO
252+ Atk Choice Band Dragonite Extreme Speed vs. 80 HP / 0 Def Nihilego: 133-157 (35 - 41.4%) -- guaranteed 3HKO
Vs Gliscor:
1. 176 SpA Nihilego Power Gem vs. 244 HP / 124 SpD Gliscor: 133-157 (37.7 - 44.6%) -- 32.6% chance to 3HKO after Poison Heal
2. 176 SpA Metronome Nihilego Power Gem vs. 244 HP / 124 SpD Gliscor: 146-173 (41.4 - 49.1%) -- not a KO
3. 176 SpA Metronome Nihilego Power Gem vs. 244 HP / 124 SpD Gliscor: 175-208 (49.7 - 59%) -- not a KO
4. 176 SpA Metronome Nihilego Power Gem vs. 244 HP / 124 SpD Gliscor: 227-270 (64.4 - 76.7%) -- not a KO
5. 176 SpA Metronome Nihilego Power Gem vs. 244 HP / 124 SpD Gliscor: 318-378 (90.3 - 107.3%) -- 43.8% chance to 1HKO after Poison Heal
Regarding Ground: This matchup is risky for Poison no matter which one you want to put in your 6th slot, Nidoking or Salazzle. Nidoking can break M-Steelix instantly but everyone realizes that, and won't allow you to do that. You also risk a Resttalk Earthquake on the pivot if you try to get Nidoking in while its mid-Rest. Also, for the same reason mentioned regarding Excadrill and Jirachi, are you perhaps talking about Choice Scarf Nidoking? You keep mentioning things Nidoking "threatens" but actually doesnt because
it is slower than both of them again. Garchomp (even mega) outspeeds and OHKO's Nidoking as does Landorus (Either Forme). Salazzle admittedly can struggle to beat M-steelix without mindgames of Sub/Toxic/Flamethrower: 0 SpA Salazzle Flamethrower vs. 248 HP / 252+ SpD Steelix-Mega: 158-188 (44.7 - 53.2%) -- 27.7% chance to 2HKO
but conversely M-steelix can also have bad RNG that is coupled with RestTalk sets, making it not use Earthquake when needed and allowing Salazzle to get behind a Substitute.
As for Electric: Fly-Z Zeraora is a 1 off move, If you predict it and let anything except Venusaur-M take it, you just got rid of Zeraora as a major threat.
+1 252 Atk Zeraora Supersonic Skystrike (160 BP) vs. 252 HP / 164+ Def Venusaur-Mega: 314-370 (86.2 - 101.6%) -- 12.5% chance to OHKO.
+1 252 Atk Zeraora Bounce vs. 252 HP / 164+ Def Venusaur-Mega: 168-198 (46.1 - 54.3%) -- 59% chance to 2HKO
Raichu-Alola with Life Orb? Are we pretending this is "new"?? It's a sweeper, everyone and their mother has tried and used that item on Raichu-Alola at some point, and probably in most cases that was the first thing they tried. I'm sorry if this seems like an insult but I can't even take that suggestion seriously enough to form a rebuttal.
And lastly: Keep the "Tours" argument out of it, I care as much about the tours as most people do about ladder peaks at this point. It is nice to see people making new and creative sets to fight each other with but does not justify an argument in the long run. The Viability Rankings are designed for the public to learn what are good choices when designing a team, so saying something (Mon or Set) is justified solely because "it was in a tour" doesn't cut it. The public for the most part doesn't watch high level tours because they play for fun, and use this forum as a place to educate themselves to make more competitive but still fun teams.