Nardole by tapping it, adding at least ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) that can only be spent to cast noncreature spells.
Cast
Mind Games with buyback by paying ({2} magic symbol) ({U} magic symbol) ({U} magic symbol) .
Chakram Retriever triggers, untapping
Nardole.
Resolve
Mind Games, tapping target artifact, creature or land and returning
Mind Games to your hand.
Repeat.
If
Nardole has at least five counters on it, this combo nets infinite ({U} magic symbol) that can only be spent to cast noncreature spells, and you may target any other creature using