Springheart Nantuko | Mutable Explorer | Nissa, Resurgent Animist (and one other card)

Cards

All permanents on the battlefield (
Springheart Nantuko attached to
Mutable Explorer).

Play a land.
When the land enters,
Springheart Nantuko triggers, causing you to pay ({1} magic symbol) ({G} magic symbol) to create three token copies of
Mutable Explorer.
When the
Mutable Explorer tokens enter, they trigger.
Resolve the first
Mutable Explorer trigger, creating a Mutavault land token that enters tapped.
When the Mutavault token enters,
Springheart Nantuko and
Nissa trigger.
Resolve the
Nissa trigger, adding ({G} magic symbol) .
Resolve the
Springheart Nantuko trigger, choosing not to pay and creating three 1/1 Insect creature tokens.
Repeat from step 4 for the second trigger.
Repeat from step 4 for the third trigger, instead choosing to pay for
Springheart Nantuko's trigger to create three token copies of
Mutable Explorer.
Repeat from step 3.

This combo has been estimated to be Exhibition (Bracket 1+).