It is not possible to recover or reactivate a deleted Pokémon Trainer Central account. Once a Pokémon Trainer Central account has been deleted, it is no longer possible to access any previous account details, including those for Play! Pokémon, Pokémon GO, or any other connected application or service.
Please see below for additional details regarding linked accounts.
Pokémon GO
If you deleted your Pokémon Trainer Central account, but you have another login method for Pokémon GO (such as through Apple or Google), it may be possible to recover your game data by contacting Scopely Explore.
Nintendo Account
If you unlinked your Nintendo Account prior to deleting your Pokémon Trainer Central account, you may link that Nintendo Account to a new Pokémon Trainer Central account.
If you did not unlink your Nintendo Account prior to deleting your Pokémon Trainer Central account, you may not link that Nintendo Account to a new Pokémon Trainer Central account.
Twitch Account
It is not possible to unlink a Twitch account from a Pokémon Trainer Central account, including if the Pokémon Trainer Central account is deleted. If a Pokémon Trainer Central account is deleted, it will not be possible to link the Twitch account to a new Pokémon Trainer Central account.