This answer is mostly just to take this question off the unanswered list. This team is for the SwSh Battle Tower classic singles. It is mostly based on another team that was made by Smogon user Stormorbiter and won 566 battles in a row.
Pheromosa @ Focus Sash
Adamant Nature
Ability: Beast Boost
EVs: 4 HP / 252 Att / 252 Spe
- Close Combat
- Lunge
- Poison Jab
- Throat Chop
Nihilego @ Power Herb
Timid Nature
Ability: Beast Boost
EVs: 184 HP / 72 SpA / 252 Spe
- Sludge Wave
- Meteor Beam
- Thunderbolt
- Grass Knot
Urshifu ♂ @ Assault Vest
Jolly Nature
Ability: Unseen Fist
EVs: 252 Att / 4 SpD / 252 Spe
- Wicked Blow
- Close Combat
- Iron Head
- Sucker Punch
Pheromosa
This is the same Pheromosa I had in my previous streak, and I really like it, so I basically built this team around it. Close Combat is the default move. Lunge, if Close Combat is ineffective. Poison Jab for fairies, and Throat Chop for Ghosts. A 1/2 effective Close Combat is still slightly more powerful than a normally effective Poison Jab or Throat Chop.
Nihilego
I wanted a Pokemon that I could switch to whenever Leon brought out his Charizard as I know Gmax Charizard is one of the few Pokemon that Pheromosa can't beat, even after a beast boost. So I wanted a Pokemon that can be a special wall, can OHKO Gmax Charizard, and isn't weak to any of Leon's Charizard's moves (fire, normal, grass, flying). As it turns out, since Nihilego is still pretty fast, it can serve as a good revenge killer for Pheromosa, and it's nice to have beast boost on top of that. Gave it just enough special attack EVs so that Beast boost still increases SpA instead of Speed. I had originally put the extra EVs into increasing SpD, but that turned out to be quite unnecessary, so HP instead served well. Meteor Beam is for Leon's Charizard (and most things that are OHKOable exclusively with it), Grass Knot is for Ground types, and Thunderbolt is the only offense Nihilego has against steel types, so had to put it on.
Urshifu
I needed someone that can beat Leon's Aegislash every time because that's another one of Pheromosa's vulnerabilities (because of shadow sneak). I also wanted someone with a speed priority move so I don't get swept by Cloyster again. Wicked Blow and Close Combat are good powerful STAB moves. Iron Head is for fairies, but he rarely goes up against them because Nihilego can beat them easily. Chose Iron Head instead of Poison Jab because I'd take flinch over poison.
Team tactics
With exceptions, have Pheromosa OHKO or THKO everyone that it can, which is most Pokemon. Else, I basically follow these rules against an opponent's lead Pokemon (so without the chance to beast boost). If against Araquanid, Golisopod, Leon's Aegislash, or Toxapex, then switch to Urshifu. If against Gyarados (with intimidate), Mimikyu, Rotom (fan), Toxtricity (blue), Vespiquen, or Weezing, then switch to Nihilego. Everyone else is either not much of a threat anyway or can be OHKO'd or THKO'd by Pheromosa with its most effective move.
How I lost:
Vs: Mantine, Pelipper, Gastrodon
Turn 1: Pheromosa Close Combat on Mantine, getting ready for a THKO, takes away more than half of Mantine's HP. Mantine uses Tailwind.
Turn 2: Mantine hits Pheromosa who is saved by focus sash. Close Combat KOs Mantine. Sends out Pelipper. Pelipper drizzles. (not good, tailwind+rain)
Turn 3: Pelipper with tailwind is faster than Pheromosa and KOs before Pheromosa has a chance. Send out Nihilego who could OHKO with a thunderbolt.
Turn 4: Or would be able to had it been able to get one off. Pelipper uses Hydro Pump and OHKOs Nihilego, which was a little surprising but not that much. I thought special wall would be able to take a hit, but the rain was the death. Now I'm nervous, but fortunately at least, tailwind peers out. Send out Urshifu.
Turn 5: I really hope I can OHKO with a Wicked Blow. Soooo close! Pelipper had like 10 HP left. Pelipper uses Hurricane, nearly OHKOs Urshifu.
Turn 6: Urshifu uses Wicked Blow and finishes off Pelipper. Sends out Gastrodon. Crap, not an OHKOable.
Turn 7: Wicked Blow doesn't OHKO Gastrodon. Gastrodon hits Urshifu to the death. Game over.
What I Could've Done Differently to Win
I should have sent out Urshifu, recognizing that Pelipper, after tailwind and drizzle, could OHKO Nihilego. Urshifu would've been sacrificed but tailwind could've gone away that turn. Nihilego would thunderbolt Pelipper, and KO Gastrodon with Grass Knot. Tailwind isn't that common, so I didn't have a whole lot of data to practice this scenario. I'll be better prepared next time!
source
There is a rule that explicitly prevents me from copying the team, so I moved 4 of Urshifu's EVs from HP to special defense. This answer now does not break any rules.
