if the land card in hand does not enter untapped and/or cannot produce mana available.
Steps
Play a land. When the land enters,
Springheart Nantuko and
Nissa trigger.
Holding priority, if the land enters the battlefield untapped, activate it by tapping it, adding at least .
Resolve the
Nissa trigger, adding .
Resolve the
Springheart Nantuko trigger, causing you to pay to create a token copy of
Astral Dragon.
When the
Astral Dragon token enters the battlefield, it triggers, creating two copies of a land you control that are 3/3 Dragon creatures in addition to their other types.
When the land tokens enter the battlefield,
Springheart Nantuko and
Nissa trigger twice.
Resolve both
Nissa triggers, adding .
Resolve the first
Springheart Nantuko trigger, choosing not to pay and creating a 1/1 Insect creature token.
Repeat from step 4 with the second
Springheart Nantuko trigger.
Results
Infinite creature ETB.
Infinite creature tokens.
Infinite landfall triggers.
Metadata
Bracket tag
SpicyBracket 3-4+
Probably 3 or 4, but hard to classify
1
2
3
4
5
1 · Exhibition5 · cEDH
Bracket tags are estimated from the cards and results of each combo, as a guideline rather than a strict classification.