1º Chansey Bold nature (It is perfect, this pokemon can sweep entire trainers on its own. I would not modify anything)
255 HP - 255 Def
Ability: Natural cure
Item: Eviolite
Minimize
Toxic
Soft-Boiled
Seismic Toss
2º Delta amoonguss Jolly nature (I should have a favorable nature in defense but I used it with this nature it worked for me)
255 HP - 255 Def
Abulity: Intimidate
Item: Leftlovers
Shadow Sneak
Night Shade (rarely use this move)
Destiny Bond (for mega aggron its perfect)
Pain Split (This is a move that you just use once, it doesn’t affect much if you change it for another, besides it doesn’t have coverage with the normal type, but that’s how I win it)
Scizor Adamant Nature
255 Att - 255 Def
Ability: Technician
Item: Scizorite (Sometimes I changed the item to focus slash but the mega is better to face other mega scyzor)
Swords Dance
Bullet Punch
U-Turn (I never used that move so you can change it for another)
Superpower
The main problems with trainers that I had are the elite four and leaders with fighting type teams my strategy is based on doing the rattrap consists of the exchange and abuse of intimidation ability to lower the attack on the fighting type that if I remember correctly they only use physical movements sometimes sacrificing chansey to boosts attack in scysor to the maximum and eliminate mega poliwrath
the other big problem for which this team faltered is against gary’s aerodactyl and his immortal exeggutor but it should not be a problem with a delta amoongus with a favorable nature in physical defense gary can only be defeated with mega scizor with maximum attack and luck in don’t get confused in front of your machamp that survives a bullet punch.
In most trainers it is expected to wear the pp with chansey except in the cases of fighting type and gary type it takes too long but it is the team that worked best for me
If someone managed to win with another team, I would like to know which team it was
I hope this team can help you to win the shadow mewtwo.